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http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #IS-BASIC | IS-BASIC | 100 PROGRAM "Combinat.bas"
110 READ N
120 STRING D$(1 TO N)*5
130 FOR I=1 TO N
140 READ D$(I)
150 NEXT
160 FOR I=1 TO N
170 FOR J=I TO N
180 PRINT D$(I);" ";D$(J)
190 NEXT
200 NEXT
210 DATA 3,iced,jam,plain |
http://rosettacode.org/wiki/Combinations_and_permutations | Combinations and permutations |
This page uses content from Wikipedia. The original article was at Combination. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
This page uses content from Wikipedia. The original article was at Permutation. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Implement the combination (nCk) and permutation (nPk) operators in the target language:
n
C
k
=
(
n
k
)
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle ^{n}\operatorname {C} _{k}={\binom {n}{k}}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
See the Wikipedia articles for a more detailed description.
To test, generate and print examples of:
A sample of permutations from 1 to 12 and Combinations from 10 to 60 using exact Integer arithmetic.
A sample of permutations from 5 to 15000 and Combinations from 100 to 1000 using approximate Floating point arithmetic.
This 'floating point' code could be implemented using an approximation, e.g., by calling the Gamma function.
Related task
Evaluate binomial coefficients
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Phix | Phix | with javascript_semantics
function P(integer n,k)
return factorial(n)/factorial(n-k)
end function
function C(integer n,k)
return P(n,k)/factorial(k)
end function
function lstirling(atom n)
if n<10 then
return lstirling(n+1)-log(n+1)
end if
return 0.5*log(2*PI*n) + n*log(n/E + 1/(12*E*n))
end function
function P_approx(integer n, k)
return lstirling(n)-lstirling(n-k)
end function
function C_approx(integer n, k)
return lstirling(n)-lstirling(n-k)-lstirling(k)
end function
function to_s(atom v)
integer e = floor(v/log(10))
return sprintf("%.9ge%d",{power(E,v-e*log(10)),e})
end function
-- Test code
printf(1,"=> Exact results:\n")
for n=1 to 12 do
integer p = floor(n/3)
printf(1,"P(%d,%d) = %d\n",{n,p,P(n,p)})
end for
for n=10 to 60 by 10 do
integer p = floor(n/3)
printf(1,"C(%d,%d) = %d\n",{n,p,C(n,p)})
end for
printf(1,"=> Floating point approximations:\n")
constant tests = {5, 50, 500, 1000, 5000, 15000}
for i=1 to length(tests) do
integer n=tests[i], p = floor(n/3)
printf(1,"P(%d,%d) = %s\n",{n,p,to_s(P_approx(n,p))})
end for
for n=100 to 1000 by 100 do
integer p = floor(n/3)
printf(1,"C(%d,%d) = %s\n",{n,p,to_s(C_approx(n,p))})
end for
|
http://rosettacode.org/wiki/Compiler/lexical_analyzer | Compiler/lexical analyzer | Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer, or scanner (though "scanner" is also used to refer to the first stage of a lexer).
Task[edit]
Create a lexical analyzer for the simple programming language specified below. The
program should read input from a file and/or stdin, and write output to a file and/or
stdout. If the language being used has a lexer module/library/class, it would be great
if two versions of the solution are provided: One without the lexer module, and one with.
Input Specification
The simple programming language to be analyzed is more or less a subset of C. It supports the following tokens:
Operators
Name
Common name
Character sequence
Op_multiply
multiply
*
Op_divide
divide
/
Op_mod
mod
%
Op_add
plus
+
Op_subtract
minus
-
Op_negate
unary minus
-
Op_less
less than
<
Op_lessequal
less than or equal
<=
Op_greater
greater than
>
Op_greaterequal
greater than or equal
>=
Op_equal
equal
==
Op_notequal
not equal
!=
Op_not
unary not
!
Op_assign
assignment
=
Op_and
logical and
&&
Op_or
logical or
¦¦
The - token should always be interpreted as Op_subtract by the lexer. Turning some Op_subtract into Op_negate will be the job of the syntax analyzer, which is not part of this task.
Symbols
Name
Common name
Character
LeftParen
left parenthesis
(
RightParen
right parenthesis
)
LeftBrace
left brace
{
RightBrace
right brace
}
Semicolon
semi-colon
;
Comma
comma
,
Keywords
Name
Character sequence
Keyword_if
if
Keyword_else
else
Keyword_while
while
Keyword_print
print
Keyword_putc
putc
Identifiers and literals
These differ from the the previous tokens, in that each occurrence of them has a value associated with it.
Name
Common name
Format description
Format regex
Value
Identifier
identifier
one or more letter/number/underscore characters, but not starting with a number
[_a-zA-Z][_a-zA-Z0-9]*
as is
Integer
integer literal
one or more digits
[0-9]+
as is, interpreted as a number
Integer
char literal
exactly one character (anything except newline or single quote) or one of the allowed escape sequences, enclosed by single quotes
'([^'\n]|\\n|\\\\)'
the ASCII code point number of the character, e.g. 65 for 'A' and 10 for '\n'
String
string literal
zero or more characters (anything except newline or double quote), enclosed by double quotes
"[^"\n]*"
the characters without the double quotes and with escape sequences converted
For char and string literals, the \n escape sequence is supported to represent a new-line character.
For char and string literals, to represent a backslash, use \\.
No other special sequences are supported. This means that:
Char literals cannot represent a single quote character (value 39).
String literals cannot represent strings containing double quote characters.
Zero-width tokens
Name
Location
End_of_input
when the end of the input stream is reached
White space
Zero or more whitespace characters, or comments enclosed in /* ... */, are allowed between any two tokens, with the exceptions noted below.
"Longest token matching" is used to resolve conflicts (e.g., in order to match <= as a single token rather than the two tokens < and =).
Whitespace is required between two tokens that have an alphanumeric character or underscore at the edge.
This means: keywords, identifiers, and integer literals.
e.g. ifprint is recognized as an identifier, instead of the keywords if and print.
e.g. 42fred is invalid, and neither recognized as a number nor an identifier.
Whitespace is not allowed inside of tokens (except for chars and strings where they are part of the value).
e.g. & & is invalid, and not interpreted as the && operator.
For example, the following two program fragments are equivalent, and should produce the same token stream except for the line and column positions:
if ( p /* meaning n is prime */ ) {
print ( n , " " ) ;
count = count + 1 ; /* number of primes found so far */
}
if(p){print(n," ");count=count+1;}
Complete list of token names
End_of_input Op_multiply Op_divide Op_mod Op_add Op_subtract
Op_negate Op_not Op_less Op_lessequal Op_greater Op_greaterequal
Op_equal Op_notequal Op_assign Op_and Op_or Keyword_if
Keyword_else Keyword_while Keyword_print Keyword_putc LeftParen RightParen
LeftBrace RightBrace Semicolon Comma Identifier Integer
String
Output Format
The program output should be a sequence of lines, each consisting of the following whitespace-separated fields:
the line number where the token starts
the column number where the token starts
the token name
the token value (only for Identifier, Integer, and String tokens)
the number of spaces between fields is up to you. Neatly aligned is nice, but not a requirement.
This task is intended to be used as part of a pipeline, with the other compiler tasks - for example:
lex < hello.t | parse | gen | vm
Or possibly:
lex hello.t lex.out
parse lex.out parse.out
gen parse.out gen.out
vm gen.out
This implies that the output of this task (the lexical analyzer) should be suitable as input to any of the Syntax Analyzer task programs.
Diagnostics
The following error conditions should be caught:
Error
Example
Empty character constant
''
Unknown escape sequence.
\r
Multi-character constant.
'xx'
End-of-file in comment. Closing comment characters not found.
End-of-file while scanning string literal. Closing string character not found.
End-of-line while scanning string literal. Closing string character not found before end-of-line.
Unrecognized character.
|
Invalid number. Starts like a number, but ends in non-numeric characters.
123abc
Test Cases
Input
Output
Test Case 1:
/*
Hello world
*/
print("Hello, World!\n");
4 1 Keyword_print
4 6 LeftParen
4 7 String "Hello, World!\n"
4 24 RightParen
4 25 Semicolon
5 1 End_of_input
Test Case 2:
/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");
4 1 Identifier phoenix_number
4 16 Op_assign
4 18 Integer 142857
4 24 Semicolon
5 1 Keyword_print
5 6 LeftParen
5 7 Identifier phoenix_number
5 21 Comma
5 23 String "\n"
5 27 RightParen
5 28 Semicolon
6 1 End_of_input
Test Case 3:
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
5 16 Keyword_print
5 40 Op_subtract
6 16 Keyword_putc
6 40 Op_less
7 16 Keyword_if
7 40 Op_greater
8 16 Keyword_else
8 40 Op_lessequal
9 16 Keyword_while
9 40 Op_greaterequal
10 16 LeftBrace
10 40 Op_equal
11 16 RightBrace
11 40 Op_notequal
12 16 LeftParen
12 40 Op_and
13 16 RightParen
13 40 Op_or
14 16 Op_subtract
14 40 Semicolon
15 16 Op_not
15 40 Comma
16 16 Op_multiply
16 40 Op_assign
17 16 Op_divide
17 40 Integer 42
18 16 Op_mod
18 40 String "String literal"
19 16 Op_add
19 40 Identifier variable_name
20 26 Integer 10
21 26 Integer 92
22 26 Integer 32
23 1 End_of_input
Test Case 4:
/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");
2 1 Keyword_print
2 6 LeftParen
2 7 Integer 42
2 9 RightParen
2 10 Semicolon
3 1 Keyword_print
3 6 LeftParen
3 7 String "\nHello World\nGood Bye\nok\n"
3 38 RightParen
3 39 Semicolon
4 1 Keyword_print
4 6 LeftParen
4 7 String "Print a slash n - \\n.\n"
4 33 RightParen
4 34 Semicolon
5 1 End_of_input
Additional examples
Your solution should pass all the test cases above and the additional tests found Here.
Reference
The C and Python versions can be considered reference implementations.
Related Tasks
Syntax Analyzer task
Code Generator task
Virtual Machine Interpreter task
AST Interpreter task
| #J | J | symbols=:256#0
ch=: {{1 0+x[symbols=: x (a.i.y)} symbols}}
'T0 token' =: 0 ch '%+-!(){};,<>=!|&'
'L0 letter' =: 1 ch '_',,u:65 97+/i.26
'D0 digit' =: 2 ch u:48+i.10
'S0 space' =: 3 ch ' ',LF
'C0 commen' =: 4 ch '/'
'C1 comment'=: 5 ch '*'
'q0 quote' =: 6 ch ''''
'Q0 dquote' =: 7 ch '"'
width=: 1+>./symbols
default=: ,:(1+i.width),every 2
states=:((1+i.width),every 1),width#default
extend=: {{
if.y>#states do.states=: y{.states,y#default
end.states
}}
pad=: {{if. 0=#y do.y=.#states end.y}}
function=: {{ NB. x: before, m: op, n: symbol, y: after
y[states=: (y,m) (<x,n)} extend 1+x>.y=.pad y
}}
{{for_op.y do.(op)=: op_index function end.0}};:'nop init start'
all=: {{y=.pad y
for_symbol.i.width do.
x symbol nop y
end.y
}}
any=: {{y=.pad y
for_symbol.i.width do.
x symbol start y
end.y
}}
NB. identifiers and keywords
L0 letter nop L0
L0 digit nop L0
NB. numbers
D0 digit nop D0
D0 letter nop D0
NB. white space
S0 space nop S0
NB. comments
C1=: C0 comment nop ''
C2=: C1 all ''
C2 all C2
C3=: C2 commen nop ''
C4=: C3 comment nop ''
NB. quoted characters
q1=: q0 any ''
NB. strings
Q1=: Q0 all ''
Q1 all Q1
Q2=: Q1 dquote nop ''
Q0 dquote nop Q2
tokenize=:{{
tok=. (0;states;symbols);:y
for_fix.cut'<= >= == != && ||'do.
M=.;:;fix
for_k.|.I.M E.tok do.
tok=.(fix,<'') (0 1+k)} tok
end.
end.tok-.a:
}}
(tknames=:;: {{)n
Op_multiply Op_divide Op_mod Op_add Op_subtract Op_less Op_lessequal
Op_greater Op_greaterequal Op_equal Op_notequal Op_not Op_and Op_or
Op_assign LeftParen RightParen Keyword_if LeftBrace Keyword_else
RightBrace Keyword_while Semicolon Keyword_print Comma Keyword_putc
}}-.LF)=: tkref=: tokenize '*/%+-<<=>>===!=!&&||=()if{else}while;print,putc'
NB. the reference tokens here were arranged to avoid whitespace tokens
NB. also, we reserve multiple token instances where a literal string
NB. appears in different syntactic productions. Here, we only use the initial
NB. instances -- the others will be used in the syntax analyzer which
NB. uses the same tkref and tknames,
shift=: |.!.0
numvals=: {{
ndx=. I.(0<#@>y)**/@> y e.L:0 '0123456789'
({{".y,'x'}}each ndx{y) ndx} y
}}
chrvals=: {{
q=. y=<,''''
s=. y=<,'\'
j=. I.(-.s)*(1&shift * _1&shift)q
k=. I.(y e.;:'\n')*(1 shift q)*(_2 shift q)*_1 shift s
jvals=. a.i.L:0 j{y NB. not escaped
kvals=. (k{s){<"0 a.i.LF,'\' NB. escaped
(,a:,jvals,:a:) (,_1 0 1+/j)} (,a:,a:,kvals,:a:) (,_2 _1 0 1+/k)} y
}}
validstring=: ((1<#)*('"'={.)*('"'={:)*('\'=])-:'\n'&E.(+._1&shift)@+.'\\'&E.) every
validid=: ((<,'\')~:_1&|.) * (e.&tkref) < (e.&(u:I.symbols=letter)@{. * */@(e.&(u:I.symbols e.letter,digit))@}.) every
lex=: {{
lineref=.I.y=LF
tokens=.(tokenize y),<,'_'
offsets=.0,}:#@;\tokens
lines=. lineref I.offsets
columns=. offsets-lines{0,lineref
keep=. -.({.@> tokens)e.u:I.space=symbols
names=. (<'End_of_input') _1} (tkref i.tokens) {(_3}.tknames),4#<'Error'
unknown=. names=<'Error'
values=. a: _1} unknown#inv numvals chrvals unknown#tokens
names=. (<'Integer') (I.(values~:a:)*tokens~:values)} names
names=. (<'String') (I.validstring tokens)} names
names=. (<'Identifier') (I.validid tokens)} names
names=. (<'End_of_input') _1} names
comments=. '*/'&-:@(_2&{.)@> tokens
whitespace=. (values=tokens) * e.&(' ',LF)@{.@> tokens
keep=. (tokens~:<,'''')*-.comments+.whitespace+.unknown*a:=values
keep&#each ((1+lines),.columns);<names,.values
}} |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #FreeBASIC | FreeBASIC | ' FB 1.05.0 Win64
' Program (myprogram.exe) invoke as follows:
' myprogram -c "alpha beta" -h "gamma"
Print "The program was invoked like this => "; Command(0) + " " + Command(-1)
Print
Print "Press any key to quit"
Sleep |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Free_Pascal | Free Pascal |
Program listArguments(input, output, stdErr);
Var
i: integer;
Begin
writeLn('program was called from: ',paramStr(0));
For i := 1 To paramCount() Do
Begin
writeLn('argument',i:2,' : ', paramStr(i));
End;
End.
|
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #C.2B.2B | C++ | // This is a comment |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Chapel | Chapel | // single line
/* multi
line */ |
http://rosettacode.org/wiki/Conway%27s_Game_of_Life | Conway's Game of Life | The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 when alive, or 0 when dead, in an m-by-m (or m×m) square array of cells.
We calculate N - the sum of live cells in C's eight-location neighbourhood, then cell C is alive or dead in the next generation based on the following table:
C N new C
1 0,1 -> 0 # Lonely
1 4,5,6,7,8 -> 0 # Overcrowded
1 2,3 -> 1 # Lives
0 3 -> 1 # It takes three to give birth!
0 0,1,2,4,5,6,7,8 -> 0 # Barren
Assume cells beyond the boundary are always dead.
The "game" is actually a zero-player game, meaning that its evolution is determined by its initial state, needing no input from human players. One interacts with the Game of Life by creating an initial configuration and observing how it evolves.
Task
Although you should test your implementation on more complex examples such as the glider in a larger universe, show the action of the blinker (three adjoining cells in a row all alive), over three generations, in a 3 by 3 grid.
References
Its creator John Conway, explains the game of life. Video from numberphile on youtube.
John Conway Inventing Game of Life - Numberphile video.
Related task
Langton's ant - another well known cellular automaton.
| #FunL | FunL | import lists.zipWithIndex
import util.Regex
data Rule( birth, survival )
val Mirek = Regex( '([0-8]+)/([0-8]+)' )
val Golly = Regex( 'B([0-8]+)/S([0-8]+)' )
def decode( rule ) =
def makerule( b, s ) = Rule( [int(d) | d <- b], [int(d) | d <- s] )
case rule
Mirek( s, b ) -> makerule( b, s )
Golly( b, s ) -> makerule( b, s )
_ -> error( "unrecognized rule: $rule" )
def fate( state, crowding, rule ) = crowding in rule( int(state) )
def crowd( buffer, x, y ) =
res = 0
def neighbour( x, y ) =
if x >= 0 and x < N and y >= 0 and y < N
res += int( buffer(x, y) )
for i <- x-1..x+1
neighbour( i, y - 1 )
neighbour( i, y + 1 )
neighbour( x - 1, y )
neighbour( x + 1, y )
res
def display( buffer ) =
for j <- 0:N
for i <- 0:N
print( if buffer(i, j) then '*' else '\u00b7' )
println()
def generation( b1, b2, rule ) =
for i <- 0:N, j <- 0:N
b2(i, j) = fate( b1(i, j), crowd(b1, i, j), rule )
def pattern( p, b, x, y ) =
for (r, j) <- zipWithIndex( list(WrappedString(p).stripMargin().split('\n')).drop(1).dropRight(1) )
for i <- 0:r.length()
b(x + i, y + j) = r(i) == '*'
var current = 0
val LIFE = decode( '23/3' )
val N = 4
val buffers = (array( N, N, (_, _) -> false ), array( N, N ))
def reset =
for i <- 0:N, j <- 0:N
buffers(0)(i, j) = false
current = 0
def iteration =
display( buffers(current) )
generation( buffers(current), buffers(current = (current + 1)%2), LIFE )
println( 5'-' )
// two patterns to be tested
blinker = '''
|
|***
'''
glider = '''
| *
| *
|***
'''
// load "blinker" pattern and run for three generations
pattern( blinker, buffers(0), 0, 0 )
repeat 3
iteration()
// clear grid, load "glider" pattern and run for five generations
reset()
pattern( glider, buffers(0), 0, 0 )
repeat 5
iteration() |
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include if-then-else and switch.
Less common are arithmetic if, ternary operator and Hash-based conditionals.
Arithmetic if allows tight control over computed gotos, which optimizers have a hard time to figure out.
| #Clipper | Clipper | IF x == 1
SomeFunc1()
ELSEIF x == 2
SomeFunc2()
ELSE
SomeFunc()
ENDIF |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #M2000_Interpreter | M2000 Interpreter |
Module CheckIt {
Function Equal(Strings){
k=Each(Strings, 2, -1)
a$=Array$(Strings, 0)
=True
While k {
=False
if a$<>array$(k) then exit
=True
}
}
Function LessThan(Strings){
=True
if len(Strings)<2 then exit
k=Each(Strings, 2)
a$=Array$(Strings, 0)
While k {
=False
if a$>=array$(k) then exit
a$=array$(k)
=True
}
}
Print Equal(("alfa","alfa","alfa", "alfa"))=True
Print Equal(("alfa",))=True
Dim A$(10)="alfa"
Print Equal(A$())=True
Print Equal(("alfa1","alfa2","alfa3", "alfa4"))=False
Print LessThan(("alfa1","alfa2","alfa3", "alfa4"))=True
Print LessThan(("alfa1",))=true
alfa$=Lambda$ k=1 ->{=String$("*", k) : k++}
Dim A$(20)<<alfa$()
Print LessThan(A$())=True
A$(5)=""
Print LessThan(A$())=False
}
Checkit
|
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #Maple | Maple | lexEqual := proc(lst)
local i:
for i from 2 to numelems(lst) do
if lst[i-1] <> lst[i] then return false: fi:
od:
return true:
end proc:
lexAscending := proc(lst)
local i:
for i from 2 to numelems(lst) do
if StringTools:-Compare(lst[i],lst[i-1]) then return false: fi:
od:
return true:
end proc:
tst := ["abc","abc","abc","abc","abc"]:
lexEqual(tst):
lexAscending(tst): |
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #EchoLisp | EchoLisp |
(lib 'match)
(define (quibble words)
(match words
[ null "{}"]
[ (a) (format "{ %a }" a)]
[ (a b) (format "{ %a and %a }" a b)]
[( a ... b c) (format "{ %a %a and %a }" (for/string ([w a]) (string-append w ", ")) b c)]
[else 'bad-input]))
;; output
(for ([t '(() ("ABC") ("ABC" "DEF") ("ABC" "DEF" "G" "H"))])
(writeln t '----> (quibble t)))
null ----> "{}"
("ABC") ----> "{ ABC }"
("ABC" "DEF") ----> "{ ABC and DEF }"
("ABC" "DEF" "G" "H") ----> "{ ABC, DEF, G and H }"
|
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #J | J | rcomb=: >@~.@:(/:~&.>)@,@{@# < |
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Java | Java |
import com.objectwave.utility.*;
public class MultiCombinationsTester {
public MultiCombinationsTester() throws CombinatoricException {
Object[] objects = {"iced", "jam", "plain"};
//Object[] objects = {"abba", "baba", "ab"};
//Object[] objects = {"aaa", "aa", "a"};
//Object[] objects = {(Integer)1, (Integer)2, (Integer)3, (Integer)4};
MultiCombinations mc = new MultiCombinations(objects, 2);
while (mc.hasMoreElements()) {
for (int i = 0; i < mc.nextElement().length; i++) {
System.out.print(mc.nextElement()[i].toString() + " ");
}
System.out.println();
}
// Extra credit:
System.out.println("----------");
System.out.println("The ways to choose 3 items from 10 with replacement = " + MultiCombinations.c(10, 3));
} // constructor
public static void main(String[] args) throws CombinatoricException {
new MultiCombinationsTester();
}
} // class
|
http://rosettacode.org/wiki/Combinations_and_permutations | Combinations and permutations |
This page uses content from Wikipedia. The original article was at Combination. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
This page uses content from Wikipedia. The original article was at Permutation. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Implement the combination (nCk) and permutation (nPk) operators in the target language:
n
C
k
=
(
n
k
)
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle ^{n}\operatorname {C} _{k}={\binom {n}{k}}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
See the Wikipedia articles for a more detailed description.
To test, generate and print examples of:
A sample of permutations from 1 to 12 and Combinations from 10 to 60 using exact Integer arithmetic.
A sample of permutations from 5 to 15000 and Combinations from 100 to 1000 using approximate Floating point arithmetic.
This 'floating point' code could be implemented using an approximation, e.g., by calling the Gamma function.
Related task
Evaluate binomial coefficients
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Python | Python | from __future__ import print_function
from scipy.misc import factorial as fact
from scipy.misc import comb
def perm(N, k, exact=0):
return comb(N, k, exact) * fact(k, exact)
exact=True
print('Sample Perms 1..12')
for N in range(1, 13):
k = max(N-2, 1)
print('%iP%i =' % (N, k), perm(N, k, exact), end=', ' if N % 5 else '\n')
print('\n\nSample Combs 10..60')
for N in range(10, 61, 10):
k = N-2
print('%iC%i =' % (N, k), comb(N, k, exact), end=', ' if N % 50 else '\n')
exact=False
print('\n\nSample Perms 5..1500 Using FP approximations')
for N in [5, 15, 150, 1500, 15000]:
k = N-2
print('%iP%i =' % (N, k), perm(N, k, exact))
print('\nSample Combs 100..1000 Using FP approximations')
for N in range(100, 1001, 100):
k = N-2
print('%iC%i =' % (N, k), comb(N, k, exact))
|
http://rosettacode.org/wiki/Compiler/lexical_analyzer | Compiler/lexical analyzer | Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer, or scanner (though "scanner" is also used to refer to the first stage of a lexer).
Task[edit]
Create a lexical analyzer for the simple programming language specified below. The
program should read input from a file and/or stdin, and write output to a file and/or
stdout. If the language being used has a lexer module/library/class, it would be great
if two versions of the solution are provided: One without the lexer module, and one with.
Input Specification
The simple programming language to be analyzed is more or less a subset of C. It supports the following tokens:
Operators
Name
Common name
Character sequence
Op_multiply
multiply
*
Op_divide
divide
/
Op_mod
mod
%
Op_add
plus
+
Op_subtract
minus
-
Op_negate
unary minus
-
Op_less
less than
<
Op_lessequal
less than or equal
<=
Op_greater
greater than
>
Op_greaterequal
greater than or equal
>=
Op_equal
equal
==
Op_notequal
not equal
!=
Op_not
unary not
!
Op_assign
assignment
=
Op_and
logical and
&&
Op_or
logical or
¦¦
The - token should always be interpreted as Op_subtract by the lexer. Turning some Op_subtract into Op_negate will be the job of the syntax analyzer, which is not part of this task.
Symbols
Name
Common name
Character
LeftParen
left parenthesis
(
RightParen
right parenthesis
)
LeftBrace
left brace
{
RightBrace
right brace
}
Semicolon
semi-colon
;
Comma
comma
,
Keywords
Name
Character sequence
Keyword_if
if
Keyword_else
else
Keyword_while
while
Keyword_print
print
Keyword_putc
putc
Identifiers and literals
These differ from the the previous tokens, in that each occurrence of them has a value associated with it.
Name
Common name
Format description
Format regex
Value
Identifier
identifier
one or more letter/number/underscore characters, but not starting with a number
[_a-zA-Z][_a-zA-Z0-9]*
as is
Integer
integer literal
one or more digits
[0-9]+
as is, interpreted as a number
Integer
char literal
exactly one character (anything except newline or single quote) or one of the allowed escape sequences, enclosed by single quotes
'([^'\n]|\\n|\\\\)'
the ASCII code point number of the character, e.g. 65 for 'A' and 10 for '\n'
String
string literal
zero or more characters (anything except newline or double quote), enclosed by double quotes
"[^"\n]*"
the characters without the double quotes and with escape sequences converted
For char and string literals, the \n escape sequence is supported to represent a new-line character.
For char and string literals, to represent a backslash, use \\.
No other special sequences are supported. This means that:
Char literals cannot represent a single quote character (value 39).
String literals cannot represent strings containing double quote characters.
Zero-width tokens
Name
Location
End_of_input
when the end of the input stream is reached
White space
Zero or more whitespace characters, or comments enclosed in /* ... */, are allowed between any two tokens, with the exceptions noted below.
"Longest token matching" is used to resolve conflicts (e.g., in order to match <= as a single token rather than the two tokens < and =).
Whitespace is required between two tokens that have an alphanumeric character or underscore at the edge.
This means: keywords, identifiers, and integer literals.
e.g. ifprint is recognized as an identifier, instead of the keywords if and print.
e.g. 42fred is invalid, and neither recognized as a number nor an identifier.
Whitespace is not allowed inside of tokens (except for chars and strings where they are part of the value).
e.g. & & is invalid, and not interpreted as the && operator.
For example, the following two program fragments are equivalent, and should produce the same token stream except for the line and column positions:
if ( p /* meaning n is prime */ ) {
print ( n , " " ) ;
count = count + 1 ; /* number of primes found so far */
}
if(p){print(n," ");count=count+1;}
Complete list of token names
End_of_input Op_multiply Op_divide Op_mod Op_add Op_subtract
Op_negate Op_not Op_less Op_lessequal Op_greater Op_greaterequal
Op_equal Op_notequal Op_assign Op_and Op_or Keyword_if
Keyword_else Keyword_while Keyword_print Keyword_putc LeftParen RightParen
LeftBrace RightBrace Semicolon Comma Identifier Integer
String
Output Format
The program output should be a sequence of lines, each consisting of the following whitespace-separated fields:
the line number where the token starts
the column number where the token starts
the token name
the token value (only for Identifier, Integer, and String tokens)
the number of spaces between fields is up to you. Neatly aligned is nice, but not a requirement.
This task is intended to be used as part of a pipeline, with the other compiler tasks - for example:
lex < hello.t | parse | gen | vm
Or possibly:
lex hello.t lex.out
parse lex.out parse.out
gen parse.out gen.out
vm gen.out
This implies that the output of this task (the lexical analyzer) should be suitable as input to any of the Syntax Analyzer task programs.
Diagnostics
The following error conditions should be caught:
Error
Example
Empty character constant
''
Unknown escape sequence.
\r
Multi-character constant.
'xx'
End-of-file in comment. Closing comment characters not found.
End-of-file while scanning string literal. Closing string character not found.
End-of-line while scanning string literal. Closing string character not found before end-of-line.
Unrecognized character.
|
Invalid number. Starts like a number, but ends in non-numeric characters.
123abc
Test Cases
Input
Output
Test Case 1:
/*
Hello world
*/
print("Hello, World!\n");
4 1 Keyword_print
4 6 LeftParen
4 7 String "Hello, World!\n"
4 24 RightParen
4 25 Semicolon
5 1 End_of_input
Test Case 2:
/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");
4 1 Identifier phoenix_number
4 16 Op_assign
4 18 Integer 142857
4 24 Semicolon
5 1 Keyword_print
5 6 LeftParen
5 7 Identifier phoenix_number
5 21 Comma
5 23 String "\n"
5 27 RightParen
5 28 Semicolon
6 1 End_of_input
Test Case 3:
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
5 16 Keyword_print
5 40 Op_subtract
6 16 Keyword_putc
6 40 Op_less
7 16 Keyword_if
7 40 Op_greater
8 16 Keyword_else
8 40 Op_lessequal
9 16 Keyword_while
9 40 Op_greaterequal
10 16 LeftBrace
10 40 Op_equal
11 16 RightBrace
11 40 Op_notequal
12 16 LeftParen
12 40 Op_and
13 16 RightParen
13 40 Op_or
14 16 Op_subtract
14 40 Semicolon
15 16 Op_not
15 40 Comma
16 16 Op_multiply
16 40 Op_assign
17 16 Op_divide
17 40 Integer 42
18 16 Op_mod
18 40 String "String literal"
19 16 Op_add
19 40 Identifier variable_name
20 26 Integer 10
21 26 Integer 92
22 26 Integer 32
23 1 End_of_input
Test Case 4:
/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");
2 1 Keyword_print
2 6 LeftParen
2 7 Integer 42
2 9 RightParen
2 10 Semicolon
3 1 Keyword_print
3 6 LeftParen
3 7 String "\nHello World\nGood Bye\nok\n"
3 38 RightParen
3 39 Semicolon
4 1 Keyword_print
4 6 LeftParen
4 7 String "Print a slash n - \\n.\n"
4 33 RightParen
4 34 Semicolon
5 1 End_of_input
Additional examples
Your solution should pass all the test cases above and the additional tests found Here.
Reference
The C and Python versions can be considered reference implementations.
Related Tasks
Syntax Analyzer task
Code Generator task
Virtual Machine Interpreter task
AST Interpreter task
| #Java | Java |
// Translated from python source
import java.io.File;
import java.io.FileNotFoundException;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
public class Lexer {
private int line;
private int pos;
private int position;
private char chr;
private String s;
Map<String, TokenType> keywords = new HashMap<>();
static class Token {
public TokenType tokentype;
public String value;
public int line;
public int pos;
Token(TokenType token, String value, int line, int pos) {
this.tokentype = token; this.value = value; this.line = line; this.pos = pos;
}
@Override
public String toString() {
String result = String.format("%5d %5d %-15s", this.line, this.pos, this.tokentype);
switch (this.tokentype) {
case Integer:
result += String.format(" %4s", value);
break;
case Identifier:
result += String.format(" %s", value);
break;
case String:
result += String.format(" \"%s\"", value);
break;
}
return result;
}
}
static enum TokenType {
End_of_input, Op_multiply, Op_divide, Op_mod, Op_add, Op_subtract,
Op_negate, Op_not, Op_less, Op_lessequal, Op_greater, Op_greaterequal,
Op_equal, Op_notequal, Op_assign, Op_and, Op_or, Keyword_if,
Keyword_else, Keyword_while, Keyword_print, Keyword_putc, LeftParen, RightParen,
LeftBrace, RightBrace, Semicolon, Comma, Identifier, Integer, String
}
static void error(int line, int pos, String msg) {
if (line > 0 && pos > 0) {
System.out.printf("%s in line %d, pos %d\n", msg, line, pos);
} else {
System.out.println(msg);
}
System.exit(1);
}
Lexer(String source) {
this.line = 1;
this.pos = 0;
this.position = 0;
this.s = source;
this.chr = this.s.charAt(0);
this.keywords.put("if", TokenType.Keyword_if);
this.keywords.put("else", TokenType.Keyword_else);
this.keywords.put("print", TokenType.Keyword_print);
this.keywords.put("putc", TokenType.Keyword_putc);
this.keywords.put("while", TokenType.Keyword_while);
}
Token follow(char expect, TokenType ifyes, TokenType ifno, int line, int pos) {
if (getNextChar() == expect) {
getNextChar();
return new Token(ifyes, "", line, pos);
}
if (ifno == TokenType.End_of_input) {
error(line, pos, String.format("follow: unrecognized character: (%d) '%c'", (int)this.chr, this.chr));
}
return new Token(ifno, "", line, pos);
}
Token char_lit(int line, int pos) {
char c = getNextChar(); // skip opening quote
int n = (int)c;
if (c == '\'') {
error(line, pos, "empty character constant");
} else if (c == '\\') {
c = getNextChar();
if (c == 'n') {
n = 10;
} else if (c == '\\') {
n = '\\';
} else {
error(line, pos, String.format("unknown escape sequence \\%c", c));
}
}
if (getNextChar() != '\'') {
error(line, pos, "multi-character constant");
}
getNextChar();
return new Token(TokenType.Integer, "" + n, line, pos);
}
Token string_lit(char start, int line, int pos) {
String result = "";
while (getNextChar() != start) {
if (this.chr == '\u0000') {
error(line, pos, "EOF while scanning string literal");
}
if (this.chr == '\n') {
error(line, pos, "EOL while scanning string literal");
}
result += this.chr;
}
getNextChar();
return new Token(TokenType.String, result, line, pos);
}
Token div_or_comment(int line, int pos) {
if (getNextChar() != '*') {
return new Token(TokenType.Op_divide, "", line, pos);
}
getNextChar();
while (true) {
if (this.chr == '\u0000') {
error(line, pos, "EOF in comment");
} else if (this.chr == '*') {
if (getNextChar() == '/') {
getNextChar();
return getToken();
}
} else {
getNextChar();
}
}
}
Token identifier_or_integer(int line, int pos) {
boolean is_number = true;
String text = "";
while (Character.isAlphabetic(this.chr) || Character.isDigit(this.chr) || this.chr == '_') {
text += this.chr;
if (!Character.isDigit(this.chr)) {
is_number = false;
}
getNextChar();
}
if (text.equals("")) {
error(line, pos, String.format("identifer_or_integer unrecognized character: (%d) %c", (int)this.chr, this.chr));
}
if (Character.isDigit(text.charAt(0))) {
if (!is_number) {
error(line, pos, String.format("invalid number: %s", text));
}
return new Token(TokenType.Integer, text, line, pos);
}
if (this.keywords.containsKey(text)) {
return new Token(this.keywords.get(text), "", line, pos);
}
return new Token(TokenType.Identifier, text, line, pos);
}
Token getToken() {
int line, pos;
while (Character.isWhitespace(this.chr)) {
getNextChar();
}
line = this.line;
pos = this.pos;
switch (this.chr) {
case '\u0000': return new Token(TokenType.End_of_input, "", this.line, this.pos);
case '/': return div_or_comment(line, pos);
case '\'': return char_lit(line, pos);
case '<': return follow('=', TokenType.Op_lessequal, TokenType.Op_less, line, pos);
case '>': return follow('=', TokenType.Op_greaterequal, TokenType.Op_greater, line, pos);
case '=': return follow('=', TokenType.Op_equal, TokenType.Op_assign, line, pos);
case '!': return follow('=', TokenType.Op_notequal, TokenType.Op_not, line, pos);
case '&': return follow('&', TokenType.Op_and, TokenType.End_of_input, line, pos);
case '|': return follow('|', TokenType.Op_or, TokenType.End_of_input, line, pos);
case '"': return string_lit(this.chr, line, pos);
case '{': getNextChar(); return new Token(TokenType.LeftBrace, "", line, pos);
case '}': getNextChar(); return new Token(TokenType.RightBrace, "", line, pos);
case '(': getNextChar(); return new Token(TokenType.LeftParen, "", line, pos);
case ')': getNextChar(); return new Token(TokenType.RightParen, "", line, pos);
case '+': getNextChar(); return new Token(TokenType.Op_add, "", line, pos);
case '-': getNextChar(); return new Token(TokenType.Op_subtract, "", line, pos);
case '*': getNextChar(); return new Token(TokenType.Op_multiply, "", line, pos);
case '%': getNextChar(); return new Token(TokenType.Op_mod, "", line, pos);
case ';': getNextChar(); return new Token(TokenType.Semicolon, "", line, pos);
case ',': getNextChar(); return new Token(TokenType.Comma, "", line, pos);
default: return identifier_or_integer(line, pos);
}
}
char getNextChar() {
this.pos++;
this.position++;
if (this.position >= this.s.length()) {
this.chr = '\u0000';
return this.chr;
}
this.chr = this.s.charAt(this.position);
if (this.chr == '\n') {
this.line++;
this.pos = 0;
}
return this.chr;
}
void printTokens() {
Token t;
while ((t = getToken()).tokentype != TokenType.End_of_input) {
System.out.println(t);
}
System.out.println(t);
}
public static void main(String[] args) {
if (args.length > 0) {
try {
File f = new File(args[0]);
Scanner s = new Scanner(f);
String source = " ";
while (s.hasNext()) {
source += s.nextLine() + "\n";
}
Lexer l = new Lexer(source);
l.printTokens();
} catch(FileNotFoundException e) {
error(-1, -1, "Exception: " + e.getMessage());
}
} else {
error(-1, -1, "No args");
}
}
}
|
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Frink | Frink |
println[ARGS]
|
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #FunL | FunL | println( args ) |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Chef | Chef | Comment Stew.
This is a comment.
The other comment is a loop, but you can name it anything (single word only).
You can also name ingredients as comments
This is pseudocode.
Ingredients.
Ingredient list
Method.
Methods.
SingleWordCommentOne the Ingredient.
Methods.
SingleWordCommentTwo until SingleWordCommentOned.
Methods. |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #ChucK | ChucK |
<-- Not common
// Usual comment
|
http://rosettacode.org/wiki/Conway%27s_Game_of_Life | Conway's Game of Life | The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 when alive, or 0 when dead, in an m-by-m (or m×m) square array of cells.
We calculate N - the sum of live cells in C's eight-location neighbourhood, then cell C is alive or dead in the next generation based on the following table:
C N new C
1 0,1 -> 0 # Lonely
1 4,5,6,7,8 -> 0 # Overcrowded
1 2,3 -> 1 # Lives
0 3 -> 1 # It takes three to give birth!
0 0,1,2,4,5,6,7,8 -> 0 # Barren
Assume cells beyond the boundary are always dead.
The "game" is actually a zero-player game, meaning that its evolution is determined by its initial state, needing no input from human players. One interacts with the Game of Life by creating an initial configuration and observing how it evolves.
Task
Although you should test your implementation on more complex examples such as the glider in a larger universe, show the action of the blinker (three adjoining cells in a row all alive), over three generations, in a 3 by 3 grid.
References
Its creator John Conway, explains the game of life. Video from numberphile on youtube.
John Conway Inventing Game of Life - Numberphile video.
Related task
Langton's ant - another well known cellular automaton.
| #Furor | Furor |
// Life simulator (game). Console (CLI) version.
// It is a 'cellular automaton', and was invented by Cambridge mathematician John Conway.
// The Rules
// For a space that is 'populated':
// Each cell with one or no neighbors dies, as if by solitude.
// Each cell with four or more neighbors dies, as if by overpopulation.
// Each cell with two or three neighbors survives.
// For a space that is 'empty' or 'unpopulated'
// Each cell with three neighbors becomes populated.
// -----------------------------------------------------
#g
// Get the terminal-resolution:
terminallines -- sto tlin
terminalcolumns sto tcol
// .............................
// Verify the commandline parameters:
argc 3 < { #s ."Usage: " 0 argv print SPACE 1 argv print ." lifeshape-file.txt\n" end }
2 argv 'f !istrue { #s ."The given file ( " 2 argv print ." ) doesn't exist!\n" end }
startingshape 2 argv filetolist // read the file into the list
startingshape maxlinelength sto maxlinlen
neighbour @tlin @tcol createlist // Generate the stringarray for the neighbour-calculations
livingspace @tlin @tcol createlist // Generate the stringarray for the actual generations
cellscreen @tlin @tcol createscreen // Generate the stringarray for the visible livingspace
// Calculate offset for the shape ( it must be put to the centre):
@tlin startingshape~ - 2 / sto originlin
@tcol @maxlinlen - 2 / sto origincol
startingshape {{|
{{}} {{|}} {{-}} [[]] 32 > { 1 }{ 0 } sto emblem
livingspace @originlin {{|}} + @origincol {{-}} + @emblem [[^]]
|}}
cursoroff
// ==================================================================
{... // infinite loop starts
sbr §renderingsbr
topleft cellscreen !printlist
."Generation: " {...} print fflush // print the number of the generations.
neighbour 0 filluplist // fill up the neighbour list with zero value
// Calculate neighbourhoods
neighbour {{|
{{|}} {{-}} sbr §neighbors
{{}} {{|}} {{-}} @n [[^]] // store the neighbournumber
|}}
// Now, kill everybody if the neighbors are less than 2 or more than 3:
neighbour {{|
{{|}} {{-}} sbr §killsbr
|}}
// Generate the newborn cells:
neighbour {{|
{{}} {{|}} {{-}} [[]] 3 == { livingspace {{|}} {{-}} 1 [[^]] }
|}}
50000 usleep
//2 sleep
...} // infinite loop ends
// ==================================================================
end
killsbr:
sto innerindex sto outerindex
neighbour @outerindex @innerindex [[]] 2 < then §kill
neighbour @outerindex @innerindex [[]] 3 > then §kill
rts
kill: livingspace @outerindex @innerindex 0 [[^]] rts
// ==========================================================
neighbors: // This subroutine calculates the quantity of neighborhood
sto y sto x zero n
livingspace @x ? @tlin -- @y ? @tcol -- [[]] sum n // upleft corner
livingspace @x ? @tlin -- @y [[]] sum n // upmid corner
livingspace @x ? @tlin -- @y ++ dup @tcol == { drop 0 } [[]] sum n // upright corner
livingspace @x @y ? @tcol -- [[]] sum n // midleft corner
livingspace @x @y ++ dup @tcol == { drop 0 } [[]] sum n // midright corner
livingspace @x ++ dup @tlin == { drop 0 } @y ? @tcol -- [[]] sum n // downleft corner
livingspace @x ++ dup @tlin == { drop 0 } @y [[]] sum n // downmid corner
livingspace @x ++ dup @tlin == { drop 0 } @y ++ dup @tcol == { drop 0 } [[]] sum n // downright corner
rts
// ==========================================================
renderingsbr:
livingspace {{|
cellscreen {{|}} {{-}}
{{}} {{|}} {{-}} [[]] { '* }{ 32 } [[^]]
|}}
rts
{ „startingshape” }
{ „livingspace” }
{ „cellscreen” }
{ „innerindex” }
{ „outerindex” }
{ „maxlinlen” }
{ „neighbour” }
{ „originlin” }
{ „origincol” }
{ „emblem” }
{ „tlin” }
{ „tcol” }
{ „x” } { „y” } { „n” }
|
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include if-then-else and switch.
Less common are arithmetic if, ternary operator and Hash-based conditionals.
Arithmetic if allows tight control over computed gotos, which optimizers have a hard time to figure out.
| #Clojure | Clojure | (if (= 1 1) :yes :no) ; returns :yes
(if (= 1 2) :yes :no) ; returns :no
(if (= 1 2) :yes) ; returns nil |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #Mathcad | Mathcad | -- define list of list of strings (nested vector of vectors of strings)
-- Mathcad vectors are single column arrays.
-- The following notation is for convenience in writing arrays in text form.
-- Mathcad array input is normally via Mathcad's array operator or via one of the
-- array-builder functions, such as stack or augment.
-- "," between vector elements indicates a new row.
-- " " between vector elements indicates a new column.
list:=["AA","AA","AA"],["AA","BB","CC"],["AA","CC","BB"],["CC","BB","AA"],["AA","ACB","BB","CC"],["AA"]]
-- define functions head and rest that return the first value in a list (vector)
-- and the list excluding the first element, respectively.
head(v):=if(IsArray(v),v[0,v)
rest(v):=if(rows(v)>1,submatrix(v,1,rows(v)-1,0,0),0)
-- define a function oprel that iterates through a list (vector) applying a comparison operator op to each pair of elements at the top of the list.
-- Returns immediately with false (0) if a comparison fails.
oprel(op,lst,val):=if(op(val,head(lst)),if(rows(lst)>1,oprel(op,rest(lst),head(lst)),1),0)
oprel(op,lst):=if(rows(lst)>1,oprel(op,rest(lst),head(lst)),1)
-- define a set of boolean comparison functions
-- transpose represents Mathcad's transpose operator
-- vectorize represents Mathcad's vectorize operator
eq(a,b):=a=b (transpose(vectorize(oprel,list))) = [1 0 0 0 0 1] -- equal
lt(a,b):=a<b (transpose(vectorize(oprel,list))) = [0 1 0 0 1 1] -- ascending
-- oprel, eq and lt also work with numeric values
list:=[11,11,11],[11,22,33],[11,33,22],[33,22,11],[11,132,22,33],[11]]
|
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #Mathematica.2FWolfram_Language | Mathematica/Wolfram Language | data1 = {"aaa", "aaa", "aab"};
Apply[Equal, data]
OrderedQ[data] |
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #Eiffel | Eiffel |
class
APPLICATION
create
make
feature
make
-- Test of the feature comma_quibbling.
local
l: LINKED_LIST [STRING]
do
create l.make
io.put_string (comma_quibbling (l) + "%N")
l.extend ("ABC")
io.put_string (comma_quibbling (l) + "%N")
l.extend ("DEF")
io.put_string (comma_quibbling (l) + "%N")
l.extend ("G")
l.extend ("H")
io.put_string (comma_quibbling (l) + "%N")
end
comma_quibbling (l: LINKED_LIST [STRING]): STRING
-- Elements of 'l' seperated by a comma or an and where appropriate.
require
l_not_void: l /= Void
do
create Result.make_empty
Result.extend ('{')
if l.is_empty then
Result.append ("}")
elseif l.count = 1 then
Result.append (l [1] + "}")
else
Result.append (l [1])
across
2 |..| (l.count - 1) as c
loop
Result.append (", " + l [c.item])
end
Result.append (" and " + l [l.count] + "}")
end
end
end
|
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #JavaScript | JavaScript | <html><head><title>Donuts</title></head>
<body><pre id='x'></pre><script type="application/javascript">
function disp(x) {
var e = document.createTextNode(x + '\n');
document.getElementById('x').appendChild(e);
}
function pick(n, got, pos, from, show) {
var cnt = 0;
if (got.length == n) {
if (show) disp(got.join(' '));
return 1;
}
for (var i = pos; i < from.length; i++) {
got.push(from[i]);
cnt += pick(n, got, i, from, show);
got.pop();
}
return cnt;
}
disp(pick(2, [], 0, ["iced", "jam", "plain"], true) + " combos");
disp("pick 3 out of 10: " + pick(3, [], 0, "a123456789".split(''), false) + " combos");
</script></body></html> |
http://rosettacode.org/wiki/Combinations_and_permutations | Combinations and permutations |
This page uses content from Wikipedia. The original article was at Combination. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
This page uses content from Wikipedia. The original article was at Permutation. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Implement the combination (nCk) and permutation (nPk) operators in the target language:
n
C
k
=
(
n
k
)
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle ^{n}\operatorname {C} _{k}={\binom {n}{k}}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
See the Wikipedia articles for a more detailed description.
To test, generate and print examples of:
A sample of permutations from 1 to 12 and Combinations from 10 to 60 using exact Integer arithmetic.
A sample of permutations from 5 to 15000 and Combinations from 100 to 1000 using approximate Floating point arithmetic.
This 'floating point' code could be implemented using an approximation, e.g., by calling the Gamma function.
Related task
Evaluate binomial coefficients
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #R | R | perm <- function(n, k) choose(n, k) * factorial(k)
print(perm(seq(from = 3, to = 12, by = 3), seq(from = 2, to = 8, by = 2)))
print(choose(seq(from = 10, to = 60, by = 10), seq(from = 3, to = 18, by = 3)))
print(perm(seq(from = 1500, to = 15000, by = 1500), seq(from = 55, to = 100, by = 5)))
print(choose(seq(from = 100, to = 1000, by = 150), seq(from = 70, to = 100, by = 5))) |
http://rosettacode.org/wiki/Compiler/lexical_analyzer | Compiler/lexical analyzer | Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer, or scanner (though "scanner" is also used to refer to the first stage of a lexer).
Task[edit]
Create a lexical analyzer for the simple programming language specified below. The
program should read input from a file and/or stdin, and write output to a file and/or
stdout. If the language being used has a lexer module/library/class, it would be great
if two versions of the solution are provided: One without the lexer module, and one with.
Input Specification
The simple programming language to be analyzed is more or less a subset of C. It supports the following tokens:
Operators
Name
Common name
Character sequence
Op_multiply
multiply
*
Op_divide
divide
/
Op_mod
mod
%
Op_add
plus
+
Op_subtract
minus
-
Op_negate
unary minus
-
Op_less
less than
<
Op_lessequal
less than or equal
<=
Op_greater
greater than
>
Op_greaterequal
greater than or equal
>=
Op_equal
equal
==
Op_notequal
not equal
!=
Op_not
unary not
!
Op_assign
assignment
=
Op_and
logical and
&&
Op_or
logical or
¦¦
The - token should always be interpreted as Op_subtract by the lexer. Turning some Op_subtract into Op_negate will be the job of the syntax analyzer, which is not part of this task.
Symbols
Name
Common name
Character
LeftParen
left parenthesis
(
RightParen
right parenthesis
)
LeftBrace
left brace
{
RightBrace
right brace
}
Semicolon
semi-colon
;
Comma
comma
,
Keywords
Name
Character sequence
Keyword_if
if
Keyword_else
else
Keyword_while
while
Keyword_print
print
Keyword_putc
putc
Identifiers and literals
These differ from the the previous tokens, in that each occurrence of them has a value associated with it.
Name
Common name
Format description
Format regex
Value
Identifier
identifier
one or more letter/number/underscore characters, but not starting with a number
[_a-zA-Z][_a-zA-Z0-9]*
as is
Integer
integer literal
one or more digits
[0-9]+
as is, interpreted as a number
Integer
char literal
exactly one character (anything except newline or single quote) or one of the allowed escape sequences, enclosed by single quotes
'([^'\n]|\\n|\\\\)'
the ASCII code point number of the character, e.g. 65 for 'A' and 10 for '\n'
String
string literal
zero or more characters (anything except newline or double quote), enclosed by double quotes
"[^"\n]*"
the characters without the double quotes and with escape sequences converted
For char and string literals, the \n escape sequence is supported to represent a new-line character.
For char and string literals, to represent a backslash, use \\.
No other special sequences are supported. This means that:
Char literals cannot represent a single quote character (value 39).
String literals cannot represent strings containing double quote characters.
Zero-width tokens
Name
Location
End_of_input
when the end of the input stream is reached
White space
Zero or more whitespace characters, or comments enclosed in /* ... */, are allowed between any two tokens, with the exceptions noted below.
"Longest token matching" is used to resolve conflicts (e.g., in order to match <= as a single token rather than the two tokens < and =).
Whitespace is required between two tokens that have an alphanumeric character or underscore at the edge.
This means: keywords, identifiers, and integer literals.
e.g. ifprint is recognized as an identifier, instead of the keywords if and print.
e.g. 42fred is invalid, and neither recognized as a number nor an identifier.
Whitespace is not allowed inside of tokens (except for chars and strings where they are part of the value).
e.g. & & is invalid, and not interpreted as the && operator.
For example, the following two program fragments are equivalent, and should produce the same token stream except for the line and column positions:
if ( p /* meaning n is prime */ ) {
print ( n , " " ) ;
count = count + 1 ; /* number of primes found so far */
}
if(p){print(n," ");count=count+1;}
Complete list of token names
End_of_input Op_multiply Op_divide Op_mod Op_add Op_subtract
Op_negate Op_not Op_less Op_lessequal Op_greater Op_greaterequal
Op_equal Op_notequal Op_assign Op_and Op_or Keyword_if
Keyword_else Keyword_while Keyword_print Keyword_putc LeftParen RightParen
LeftBrace RightBrace Semicolon Comma Identifier Integer
String
Output Format
The program output should be a sequence of lines, each consisting of the following whitespace-separated fields:
the line number where the token starts
the column number where the token starts
the token name
the token value (only for Identifier, Integer, and String tokens)
the number of spaces between fields is up to you. Neatly aligned is nice, but not a requirement.
This task is intended to be used as part of a pipeline, with the other compiler tasks - for example:
lex < hello.t | parse | gen | vm
Or possibly:
lex hello.t lex.out
parse lex.out parse.out
gen parse.out gen.out
vm gen.out
This implies that the output of this task (the lexical analyzer) should be suitable as input to any of the Syntax Analyzer task programs.
Diagnostics
The following error conditions should be caught:
Error
Example
Empty character constant
''
Unknown escape sequence.
\r
Multi-character constant.
'xx'
End-of-file in comment. Closing comment characters not found.
End-of-file while scanning string literal. Closing string character not found.
End-of-line while scanning string literal. Closing string character not found before end-of-line.
Unrecognized character.
|
Invalid number. Starts like a number, but ends in non-numeric characters.
123abc
Test Cases
Input
Output
Test Case 1:
/*
Hello world
*/
print("Hello, World!\n");
4 1 Keyword_print
4 6 LeftParen
4 7 String "Hello, World!\n"
4 24 RightParen
4 25 Semicolon
5 1 End_of_input
Test Case 2:
/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");
4 1 Identifier phoenix_number
4 16 Op_assign
4 18 Integer 142857
4 24 Semicolon
5 1 Keyword_print
5 6 LeftParen
5 7 Identifier phoenix_number
5 21 Comma
5 23 String "\n"
5 27 RightParen
5 28 Semicolon
6 1 End_of_input
Test Case 3:
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
5 16 Keyword_print
5 40 Op_subtract
6 16 Keyword_putc
6 40 Op_less
7 16 Keyword_if
7 40 Op_greater
8 16 Keyword_else
8 40 Op_lessequal
9 16 Keyword_while
9 40 Op_greaterequal
10 16 LeftBrace
10 40 Op_equal
11 16 RightBrace
11 40 Op_notequal
12 16 LeftParen
12 40 Op_and
13 16 RightParen
13 40 Op_or
14 16 Op_subtract
14 40 Semicolon
15 16 Op_not
15 40 Comma
16 16 Op_multiply
16 40 Op_assign
17 16 Op_divide
17 40 Integer 42
18 16 Op_mod
18 40 String "String literal"
19 16 Op_add
19 40 Identifier variable_name
20 26 Integer 10
21 26 Integer 92
22 26 Integer 32
23 1 End_of_input
Test Case 4:
/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");
2 1 Keyword_print
2 6 LeftParen
2 7 Integer 42
2 9 RightParen
2 10 Semicolon
3 1 Keyword_print
3 6 LeftParen
3 7 String "\nHello World\nGood Bye\nok\n"
3 38 RightParen
3 39 Semicolon
4 1 Keyword_print
4 6 LeftParen
4 7 String "Print a slash n - \\n.\n"
4 33 RightParen
4 34 Semicolon
5 1 End_of_input
Additional examples
Your solution should pass all the test cases above and the additional tests found Here.
Reference
The C and Python versions can be considered reference implementations.
Related Tasks
Syntax Analyzer task
Code Generator task
Virtual Machine Interpreter task
AST Interpreter task
| #JavaScript | JavaScript |
/*
Token: type, value, line, pos
*/
const TokenType = {
Keyword_if: 1, Keyword_else: 2, Keyword_print: 3, Keyword_putc: 4, Keyword_while: 5,
Op_add: 6, Op_and: 7, Op_assign: 8, Op_divide: 9, Op_equal: 10, Op_greater: 11,
Op_greaterequal: 12, Op_less: 13, Op_Lessequal: 14, Op_mod: 15, Op_multiply: 16, Op_not: 17,
Op_notequal: 18, Op_or: 19, Op_subtract: 20,
Integer: 21, String: 22, Identifier: 23,
Semicolon: 24, Comma: 25,
LeftBrace: 26, RightBrace: 27,
LeftParen: 28, RightParen: 29,
End_of_input: 99
}
class Lexer {
constructor(source) {
this.source = source
this.pos = 1 // position in line
this.position = 0 // position in source
this.line = 1
this.chr = this.source.charAt(0)
this.keywords = {
"if": TokenType.Keyword_if,
"else": TokenType.Keyword_else,
"print": TokenType.Keyword_print,
"putc": TokenType.Keyword_putc,
"while": TokenType.Keyword_while
}
}
getNextChar() {
this.pos++
this.position++
if (this.position >= this.source.length) {
this.chr = undefined
return this.chr
}
this.chr = this.source.charAt(this.position)
if (this.chr === '\n') {
this.line++
this.pos = 0
}
return this.chr
}
error(line, pos, message) {
if (line > 0 && pos > 0) {
console.log(message + " in line " + line + ", pos " + pos + "\n")
} else {
console.log(message)
}
process.exit(1)
}
follow(expect, ifyes, ifno, line, pos) {
if (this.getNextChar() === expect) {
this.getNextChar()
return { type: ifyes, value: "", line, pos }
}
if (ifno === TokenType.End_of_input) {
this.error(line, pos, "follow: unrecognized character: (" + this.chr.charCodeAt(0) + ") '" + this.chr + "'")
}
return { type: ifno, value: "", line, pos }
}
div_or_comment(line, pos) {
if (this.getNextChar() !== '*') {
return { type: TokenType.Op_divide, value: "/", line, pos }
}
this.getNextChar()
while (true) {
if (this.chr === '\u0000') {
this.error(line, pos, "EOF in comment")
} else if (this.chr === '*') {
if (this.getNextChar() === '/') {
this.getNextChar()
return this.getToken()
}
} else {
this.getNextChar()
}
}
}
char_lit(line, pos) {
let c = this.getNextChar() // skip opening quote
let n = c.charCodeAt(0)
if (c === "\'") {
this.error(line, pos, "empty character constant")
} else if (c === "\\") {
c = this.getNextChar()
if (c == "n") {
n = 10
} else if (c === "\\") {
n = 92
} else {
this.error(line, pos, "unknown escape sequence \\" + c)
}
}
if (this.getNextChar() !== "\'") {
this.error(line, pos, "multi-character constant")
}
this.getNextChar()
return { type: TokenType.Integer, value: n, line, pos }
}
string_lit(start, line, pos) {
let value = ""
while (this.getNextChar() !== start) {
if (this.chr === undefined) {
this.error(line, pos, "EOF while scanning string literal")
}
if (this.chr === "\n") {
this.error(line, pos, "EOL while scanning string literal")
}
value += this.chr
}
this.getNextChar()
return { type: TokenType.String, value, line, pos }
}
identifier_or_integer(line, pos) {
let is_number = true
let text = ""
while (/\w/.test(this.chr) || this.chr === '_') {
text += this.chr
if (!/\d/.test(this.chr)) {
is_number = false
}
this.getNextChar()
}
if (text === "") {
this.error(line, pos, "identifer_or_integer unrecopgnized character: follow: unrecognized character: (" + this.chr.charCodeAt(0) + ") '" + this.chr + "'")
}
if (/\d/.test(text.charAt(0))) {
if (!is_number) {
this.error(line, pos, "invaslid number: " + text)
}
return { type: TokenType.Integer, value: text, line, pos }
}
if (text in this.keywords) {
return { type: this.keywords[text], value: "", line, pos }
}
return { type: TokenType.Identifier, value: text, line, pos }
}
getToken() {
let pos, line
// Ignore whitespaces
while (/\s/.test(this.chr)) { this.getNextChar() }
line = this.line; pos = this.pos
switch (this.chr) {
case undefined: return { type: TokenType.End_of_input, value: "", line: this.line, pos: this.pos }
case "/": return this.div_or_comment(line, pos)
case "\'": return this.char_lit(line, pos)
case "\"": return this.string_lit(this.chr, line, pos)
case "<": return this.follow("=", TokenType.Op_lessequal, TokenType.Op_less, line, pos)
case ">": return this.follow("=", TokenType.Op_greaterequal, TokenType.Op_greater, line, pos)
case "=": return this.follow("=", TokenType.Op_equal, TokenType.Op_assign, line, pos)
case "!": return this.follow("=", TokenType.Op_notequal, TokenType.Op_not, line, pos)
case "&": return this.follow("&", TokenType.Op_and, TokenType.End_of_input, line, pos)
case "|": return this.follow("|", TokenType.Op_or, TokenType.End_of_input, line, pos)
case "{": this.getNextChar(); return { type: TokenType.LeftBrace, value: "{", line, pos }
case "}": this.getNextChar(); return { type: TokenType.RightBrace, value: "}", line, pos }
case "(": this.getNextChar(); return { type: TokenType.LeftParen, value: "(", line, pos }
case ")": this.getNextChar(); return { type: TokenType.RightParen, value: ")", line, pos }
case "+": this.getNextChar(); return { type: TokenType.Op_add, value: "+", line, pos }
case "-": this.getNextChar(); return { type: TokenType.Op_subtract, value: "-", line, pos }
case "*": this.getNextChar(); return { type: TokenType.Op_multiply, value: "*", line, pos }
case "%": this.getNextChar(); return { type: TokenType.Op_mod, value: "%", line, pos }
case ";": this.getNextChar(); return { type: TokenType.Semicolon, value: ";", line, pos }
case ",": this.getNextChar(); return { type: TokenType.Comma, value: ",", line, pos }
default: return this.identifier_or_integer(line, pos)
}
}
/*
https://stackoverflow.com/questions/9907419/how-to-get-a-key-in-a-javascript-object-by-its-value
*/
getTokenType(value) {
return Object.keys(TokenType).find(key => TokenType[key] === value)
}
printToken(t) {
let result = (" " + t.line).substr(t.line.toString().length)
result += (" " + t.pos).substr(t.pos.toString().length)
result += (" " + this.getTokenType(t.type) + " ").substr(0, 16)
switch (t.type) {
case TokenType.Integer:
result += " " + t.value
break;
case TokenType.Identifier:
result += " " + t.value
break;
case TokenType.String:
result += " \""+ t.value + "\""
break;
}
console.log(result)
}
printTokens() {
let t
while ((t = this.getToken()).type !== TokenType.End_of_input) {
this.printToken(t)
}
this.printToken(t)
}
}
const fs = require("fs")
fs.readFile(process.argv[2], "utf8", (err, data) => {
l = new Lexer(data)
l.printTokens()
})
|
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Gambas | Gambas | PUBLIC SUB main()
DIM l AS Integer
DIM numparms AS Integer
DIM parm AS String
numparms = Application.Args.Count
FOR l = 0 TO numparms - 1
parm = Application.Args[l]
PRINT l; " : "; parm
NEXT
END |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Genie | Genie | [indent=4]
/*
Command line arguments, in Genie
valac commandLine.gs
./commandLine sample arguments 'four in total here, including args 0'
*/
init
// Output the number of arguments
print "%d command line argument(s):", args.length
// Enumerate all command line arguments
for s in args
print s
// to reiterate, args[0] is the command
if args[0] is not null
print "\nWith Genie, args[0] is the command: %s", args[0] |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Clean | Clean | Start = /* This is a multi-
line comment */ 17 // This is a single-line comment |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Clojure | Clojure | ;; This is a comment
(defn foo []
123) ; also a comment |
http://rosettacode.org/wiki/Conway%27s_Game_of_Life | Conway's Game of Life | The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 when alive, or 0 when dead, in an m-by-m (or m×m) square array of cells.
We calculate N - the sum of live cells in C's eight-location neighbourhood, then cell C is alive or dead in the next generation based on the following table:
C N new C
1 0,1 -> 0 # Lonely
1 4,5,6,7,8 -> 0 # Overcrowded
1 2,3 -> 1 # Lives
0 3 -> 1 # It takes three to give birth!
0 0,1,2,4,5,6,7,8 -> 0 # Barren
Assume cells beyond the boundary are always dead.
The "game" is actually a zero-player game, meaning that its evolution is determined by its initial state, needing no input from human players. One interacts with the Game of Life by creating an initial configuration and observing how it evolves.
Task
Although you should test your implementation on more complex examples such as the glider in a larger universe, show the action of the blinker (three adjoining cells in a row all alive), over three generations, in a 3 by 3 grid.
References
Its creator John Conway, explains the game of life. Video from numberphile on youtube.
John Conway Inventing Game of Life - Numberphile video.
Related task
Langton's ant - another well known cellular automaton.
| #Futhark | Futhark |
fun bint(b: bool): int = if b then 1 else 0
fun intb(x: int): bool = if x == 0 then False else True
fun to_bool_board(board: [][]int): [][]bool =
map (fn (r: []int): []bool => map intb r) board
fun to_int_board(board: [][]bool): [][]int =
map (fn (r: []bool): []int => map bint r) board
fun cell_neighbors(i: int, j: int, board: [n][m]bool): int =
unsafe
let above = (i - 1) % n
let below = (i + 1) % n
let right = (j + 1) % m
let left = (j - 1) % m in
bint board[above,left] + bint board[above,j] + bint board[above,right] +
bint board[i,left] + bint board[i,right] +
bint board[below,left] + bint board[below,j] + bint board[below,right]
fun all_neighbours(board: [n][m]bool): [n][m]int =
map (fn (i: int): []int =>
map (fn (j: int): int => cell_neighbors(i,j,board)) (iota m))
(iota n)
fun iteration(board: [n][m]bool): [n][m]bool =
let lives = all_neighbours(board) in
zipWith (fn (lives_r: []int) (board_r: []bool): []bool =>
zipWith (fn (neighbors: int) (alive: bool): bool =>
if neighbors < 2
then False
else if neighbors == 3 then True
else if alive && neighbors < 4 then True
else False)
lives_r board_r)
lives board
fun main(int_board: [][]int, iterations: int): [][]int =
-- We accept the board as integers for convenience, and then we
-- convert to booleans here.
let board = to_bool_board int_board in
loop (board) = for i < iterations do
iteration board in
to_int_board board
|
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include if-then-else and switch.
Less common are arithmetic if, ternary operator and Hash-based conditionals.
Arithmetic if allows tight control over computed gotos, which optimizers have a hard time to figure out.
| #CMake | CMake | set(num 5)
if(num GREATER 100)
message("${num} is very large!")
elseif(num GREATER 10)
message("${num} is large.")
else()
message("${num} is small.")
message("We might want a bigger number.")
endif() |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #MATLAB_.2F_Octave | MATLAB / Octave | alist = {'aa', 'aa', 'aa'}
all(strcmp(alist,alist{1})) |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #Nanoquery | Nanoquery | // a function to test if a list of strings are equal
def stringsEqual(stringList)
// if the list is empty, return true
if (len(stringList) = 0)
return true
end
// otherwise get the first value and check for equality
toCompare = stringList[0]
equal = true
for (i = 1) (equal && (i < len(stringList))) (i = i + 1)
equal = (toCompare = stringList[i])
end for
// return whether the strings are equal or not
return equal
end
// a function to test if a list of strings are are less than each other
def stringsLessThan(stringList)
// if the list is empty, return true
if (len(stringList) = 0)
return true
end
// otherwise get the first value and check for less than
toCompare = stringList[0]
lessThan = true
for (i = 1) (lessThan && (i < len(stringList))) (i = i + 1)
lessThan = (toCompare < stringList[i])
toCompare = stringList[i]
end for
// return whether the string were less than each other or not
return lessThan
end |
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #Elixir | Elixir | defmodule RC do
def generate( list ), do: "{#{ generate_content(list) }}"
defp generate_content( [] ), do: ""
defp generate_content( [x] ), do: x
defp generate_content( [x1, x2] ), do: "#{x1} and #{x2}"
defp generate_content( xs ) do
[last, second_to_last | t] = Enum.reverse( xs )
with_commas = for x <- t, do: x <> ","
Enum.join(Enum.reverse([last, "and", second_to_last | with_commas]), " ")
end
end
Enum.each([[], ["ABC"], ["ABC", "DEF"], ["ABC", "DEF", "G", "H"]], fn list ->
IO.inspect RC.generate(list)
end) |
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #Erlang | Erlang |
-module( comma_quibbling ).
-export( [task/0] ).
task() -> [generate(X) || X <- [[], ["ABC"], ["ABC", "DEF"], ["ABC", "DEF", "G", "H"]]].
generate( List ) -> "{" ++ generate_content(List) ++ "}".
generate_content( [] ) -> "";
generate_content( [X] ) -> X;
generate_content( [X1, X2] ) -> string:join( [X1, "and", X2], " " );
generate_content( Xs ) ->
[Last, Second_to_last | T] = lists:reverse( Xs ),
With_commas = [X ++ "," || X <- T],
string:join(lists:reverse([Last, "and", Second_to_last | With_commas]), " ").
|
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #jq | jq | def pick(n):
def pick(n; m): # pick n, from m onwards
if n == 0 then []
elif m == length then empty
elif n == 1 then (.[m:][] | [.])
else ([.[m]] + pick(n-1; m)), pick(n; m+1)
end;
pick(n;0) ; |
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Julia | Julia | using Combinatorics
l = ["iced", "jam", "plain"]
println("List: ", l, "\nCombinations:")
for c in with_replacement_combinations(l, 2)
println(c)
end
@show length(with_replacement_combinations(1:10, 3)) |
http://rosettacode.org/wiki/Combinations_and_permutations | Combinations and permutations |
This page uses content from Wikipedia. The original article was at Combination. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
This page uses content from Wikipedia. The original article was at Permutation. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Implement the combination (nCk) and permutation (nPk) operators in the target language:
n
C
k
=
(
n
k
)
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle ^{n}\operatorname {C} _{k}={\binom {n}{k}}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
See the Wikipedia articles for a more detailed description.
To test, generate and print examples of:
A sample of permutations from 1 to 12 and Combinations from 10 to 60 using exact Integer arithmetic.
A sample of permutations from 5 to 15000 and Combinations from 100 to 1000 using approximate Floating point arithmetic.
This 'floating point' code could be implemented using an approximation, e.g., by calling the Gamma function.
Related task
Evaluate binomial coefficients
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Racket | Racket |
#lang racket
(require math)
(define C binomial)
(define P permutations)
(C 1000 10) ; -> 263409560461970212832400
(P 1000 10) ; -> 955860613004397508326213120000
|
http://rosettacode.org/wiki/Combinations_and_permutations | Combinations and permutations |
This page uses content from Wikipedia. The original article was at Combination. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
This page uses content from Wikipedia. The original article was at Permutation. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Implement the combination (nCk) and permutation (nPk) operators in the target language:
n
C
k
=
(
n
k
)
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle ^{n}\operatorname {C} _{k}={\binom {n}{k}}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
See the Wikipedia articles for a more detailed description.
To test, generate and print examples of:
A sample of permutations from 1 to 12 and Combinations from 10 to 60 using exact Integer arithmetic.
A sample of permutations from 5 to 15000 and Combinations from 100 to 1000 using approximate Floating point arithmetic.
This 'floating point' code could be implemented using an approximation, e.g., by calling the Gamma function.
Related task
Evaluate binomial coefficients
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Raku | Raku | multi P($n, $k) { [*] $n - $k + 1 .. $n }
multi C($n, $k) { P($n, $k) / [*] 1 .. $k }
sub lstirling(\n) {
n < 10 ?? lstirling(n+1) - log(n+1) !!
.5*log(2*pi*n)+ n*log(n/e+1/(12*e*n))
}
role Logarithm {
method gist {
my $e = (self/10.log).Int;
sprintf "%.8fE%+d", exp(self - $e*10.log), $e;
}
}
multi P($n, $k, :$float!) {
(lstirling($n) - lstirling($n -$k))
but Logarithm
}
multi C($n, $k, :$float!) {
(lstirling($n) - lstirling($n -$k) - lstirling($k))
but Logarithm
}
say "Exact results:";
for 1..12 -> $n {
my $p = $n div 3;
say "P($n, $p) = ", P($n, $p);
}
for 10, 20 ... 60 -> $n {
my $p = $n div 3;
say "C($n, $p) = ", C($n, $p);
}
say '';
say "Floating point approximations:";
for 5, 50, 500, 1000, 5000, 15000 -> $n {
my $p = $n div 3;
say "P($n, $p) = ", P($n, $p, :float);
}
for 100, 200 ... 1000 -> $n {
my $p = $n div 3;
say "C($n, $p) = ", C($n, $p, :float);
} |
http://rosettacode.org/wiki/Compiler/lexical_analyzer | Compiler/lexical analyzer | Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer, or scanner (though "scanner" is also used to refer to the first stage of a lexer).
Task[edit]
Create a lexical analyzer for the simple programming language specified below. The
program should read input from a file and/or stdin, and write output to a file and/or
stdout. If the language being used has a lexer module/library/class, it would be great
if two versions of the solution are provided: One without the lexer module, and one with.
Input Specification
The simple programming language to be analyzed is more or less a subset of C. It supports the following tokens:
Operators
Name
Common name
Character sequence
Op_multiply
multiply
*
Op_divide
divide
/
Op_mod
mod
%
Op_add
plus
+
Op_subtract
minus
-
Op_negate
unary minus
-
Op_less
less than
<
Op_lessequal
less than or equal
<=
Op_greater
greater than
>
Op_greaterequal
greater than or equal
>=
Op_equal
equal
==
Op_notequal
not equal
!=
Op_not
unary not
!
Op_assign
assignment
=
Op_and
logical and
&&
Op_or
logical or
¦¦
The - token should always be interpreted as Op_subtract by the lexer. Turning some Op_subtract into Op_negate will be the job of the syntax analyzer, which is not part of this task.
Symbols
Name
Common name
Character
LeftParen
left parenthesis
(
RightParen
right parenthesis
)
LeftBrace
left brace
{
RightBrace
right brace
}
Semicolon
semi-colon
;
Comma
comma
,
Keywords
Name
Character sequence
Keyword_if
if
Keyword_else
else
Keyword_while
while
Keyword_print
print
Keyword_putc
putc
Identifiers and literals
These differ from the the previous tokens, in that each occurrence of them has a value associated with it.
Name
Common name
Format description
Format regex
Value
Identifier
identifier
one or more letter/number/underscore characters, but not starting with a number
[_a-zA-Z][_a-zA-Z0-9]*
as is
Integer
integer literal
one or more digits
[0-9]+
as is, interpreted as a number
Integer
char literal
exactly one character (anything except newline or single quote) or one of the allowed escape sequences, enclosed by single quotes
'([^'\n]|\\n|\\\\)'
the ASCII code point number of the character, e.g. 65 for 'A' and 10 for '\n'
String
string literal
zero or more characters (anything except newline or double quote), enclosed by double quotes
"[^"\n]*"
the characters without the double quotes and with escape sequences converted
For char and string literals, the \n escape sequence is supported to represent a new-line character.
For char and string literals, to represent a backslash, use \\.
No other special sequences are supported. This means that:
Char literals cannot represent a single quote character (value 39).
String literals cannot represent strings containing double quote characters.
Zero-width tokens
Name
Location
End_of_input
when the end of the input stream is reached
White space
Zero or more whitespace characters, or comments enclosed in /* ... */, are allowed between any two tokens, with the exceptions noted below.
"Longest token matching" is used to resolve conflicts (e.g., in order to match <= as a single token rather than the two tokens < and =).
Whitespace is required between two tokens that have an alphanumeric character or underscore at the edge.
This means: keywords, identifiers, and integer literals.
e.g. ifprint is recognized as an identifier, instead of the keywords if and print.
e.g. 42fred is invalid, and neither recognized as a number nor an identifier.
Whitespace is not allowed inside of tokens (except for chars and strings where they are part of the value).
e.g. & & is invalid, and not interpreted as the && operator.
For example, the following two program fragments are equivalent, and should produce the same token stream except for the line and column positions:
if ( p /* meaning n is prime */ ) {
print ( n , " " ) ;
count = count + 1 ; /* number of primes found so far */
}
if(p){print(n," ");count=count+1;}
Complete list of token names
End_of_input Op_multiply Op_divide Op_mod Op_add Op_subtract
Op_negate Op_not Op_less Op_lessequal Op_greater Op_greaterequal
Op_equal Op_notequal Op_assign Op_and Op_or Keyword_if
Keyword_else Keyword_while Keyword_print Keyword_putc LeftParen RightParen
LeftBrace RightBrace Semicolon Comma Identifier Integer
String
Output Format
The program output should be a sequence of lines, each consisting of the following whitespace-separated fields:
the line number where the token starts
the column number where the token starts
the token name
the token value (only for Identifier, Integer, and String tokens)
the number of spaces between fields is up to you. Neatly aligned is nice, but not a requirement.
This task is intended to be used as part of a pipeline, with the other compiler tasks - for example:
lex < hello.t | parse | gen | vm
Or possibly:
lex hello.t lex.out
parse lex.out parse.out
gen parse.out gen.out
vm gen.out
This implies that the output of this task (the lexical analyzer) should be suitable as input to any of the Syntax Analyzer task programs.
Diagnostics
The following error conditions should be caught:
Error
Example
Empty character constant
''
Unknown escape sequence.
\r
Multi-character constant.
'xx'
End-of-file in comment. Closing comment characters not found.
End-of-file while scanning string literal. Closing string character not found.
End-of-line while scanning string literal. Closing string character not found before end-of-line.
Unrecognized character.
|
Invalid number. Starts like a number, but ends in non-numeric characters.
123abc
Test Cases
Input
Output
Test Case 1:
/*
Hello world
*/
print("Hello, World!\n");
4 1 Keyword_print
4 6 LeftParen
4 7 String "Hello, World!\n"
4 24 RightParen
4 25 Semicolon
5 1 End_of_input
Test Case 2:
/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");
4 1 Identifier phoenix_number
4 16 Op_assign
4 18 Integer 142857
4 24 Semicolon
5 1 Keyword_print
5 6 LeftParen
5 7 Identifier phoenix_number
5 21 Comma
5 23 String "\n"
5 27 RightParen
5 28 Semicolon
6 1 End_of_input
Test Case 3:
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
5 16 Keyword_print
5 40 Op_subtract
6 16 Keyword_putc
6 40 Op_less
7 16 Keyword_if
7 40 Op_greater
8 16 Keyword_else
8 40 Op_lessequal
9 16 Keyword_while
9 40 Op_greaterequal
10 16 LeftBrace
10 40 Op_equal
11 16 RightBrace
11 40 Op_notequal
12 16 LeftParen
12 40 Op_and
13 16 RightParen
13 40 Op_or
14 16 Op_subtract
14 40 Semicolon
15 16 Op_not
15 40 Comma
16 16 Op_multiply
16 40 Op_assign
17 16 Op_divide
17 40 Integer 42
18 16 Op_mod
18 40 String "String literal"
19 16 Op_add
19 40 Identifier variable_name
20 26 Integer 10
21 26 Integer 92
22 26 Integer 32
23 1 End_of_input
Test Case 4:
/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");
2 1 Keyword_print
2 6 LeftParen
2 7 Integer 42
2 9 RightParen
2 10 Semicolon
3 1 Keyword_print
3 6 LeftParen
3 7 String "\nHello World\nGood Bye\nok\n"
3 38 RightParen
3 39 Semicolon
4 1 Keyword_print
4 6 LeftParen
4 7 String "Print a slash n - \\n.\n"
4 33 RightParen
4 34 Semicolon
5 1 End_of_input
Additional examples
Your solution should pass all the test cases above and the additional tests found Here.
Reference
The C and Python versions can be considered reference implementations.
Related Tasks
Syntax Analyzer task
Code Generator task
Virtual Machine Interpreter task
AST Interpreter task
| #Julia | Julia | struct Tokenized
startline::Int
startcol::Int
name::String
value::Union{Nothing, Int, String}
end
const optokens = Dict("*" => "Op_multiply", "/" => "Op_divide", "%" => "Op_mod", "+" => "Op_add",
"-" => "Op_subtract", "!" => "Op_not", "<" => "Op_less", "<=" => "Op_lessequal",
">" => "Op_greater", ">=" => "Op_greaterequal", "==" => "Op_equal", "!=" => "Op_notequal",
"!" => "Op_not", "=" => "Op_assign", "&&" => "Op_and", "||" => "Op_or")
const keywordtokens = Dict("if" => "Keyword_if", "else" => "Keyword_else", "while" => "Keyword_while",
"print" => "Keyword_print", "putc" => "Keyword_putc")
const symboltokens = Dict("(" => "LeftParen", ")" => "RightParen", "{" => "LeftBrace",
"}" => "RightBrace", ";" => "Semicolon", "," => "Comma")
const errors = ["Empty character constant.", "Unknown escape sequence.", "Multi-character constant.",
"End-of-file in comment. Closing comment characters not found.",
"End-of-file while scanning string literal. Closing string character not found.",
"End-of-line while scanning string literal. Closing string character not found before end-of-line.",
"Unrecognized character.", "Invalid number. Starts like a number, but ends in non-numeric characters."]
asws(s) = (nnl = length(findall(x->x=='\n', s)); " " ^ (length(s) - nnl) * "\n" ^ nnl)
comment2ws(t) = (while occursin("/*", t) t = replace(t, r"\/\* .+? (?: \*\/)"xs => asws; count = 1) end; t)
hasinvalidescapes(t) = ((m = match(r"\\.", t)) != nothing && m.match != "\\\\" && m.match != "\\n")
hasemptycharconstant(t) = (match(r"\'\'", t) != nothing)
hasmulticharconstant(t) = ((m = match(r"\'[^\'][^\']+\'", t)) != nothing && m.match != "\'\\\\\'" && m.match != "\'\\n\'")
hasunbalancedquotes(t) = isodd(length(findall(x -> x == '\"', t)))
hasunrecognizedchar(t) = match(r"[^\w\s\d\*\/\%\+\-\<\>\=\!\&\|\(\)\{\}\;\,\"\'\\]", t) != nothing
function throwiferror(line, n)
if hasemptycharconstant(line)
throw("Tokenizer error line $n: " * errors[1])
end
if hasinvalidescapes(line)
throw("Tokenizer error line $n: " * errors[2])
end
if hasmulticharconstant(line)
println("error at ", match(r"\'[^\'][^\']+\'", line).match)
throw("Tokenizer error line $n: " * errors[3])
end
if occursin("/*", line)
throw("Tokenizer error line $n: " * errors[4])
end
if hasunrecognizedchar(line)
throw("Tokenizer error line $n: " * errors[7])
end
end
function tokenize(txt)
tokens = Vector{Tokenized}()
txt = comment2ws(txt)
lines = split(txt, "\n")
if hasunbalancedquotes(txt)
throw("Tokenizer error: $(errors[5])")
end
for (startline, line) in enumerate(lines)
if strip(line) == ""
continue
end
throwiferror(line, startline)
lastc = Char(0)
withintoken = 0
for (startcol, c) in enumerate(line)
if withintoken > 0
withintoken -= 1
continue
elseif isspace(c[1])
continue
elseif (c == '=') && (startcol > 1) && ((c2 = line[startcol - 1]) in ['<', '>', '=', '!'])
tokens[end] = Tokenized(startline, startcol - 1, optokens[c2 * c], nothing)
elseif (c == '&') || (c == '|')
if length(line) > startcol && line[startcol + 1] == c
push!(tokens, Tokenized(startline, startcol, optokens[c * c], nothing))
withintoken = 1
else
throw("Tokenizer error line $startline: $(errors[7])")
end
elseif haskey(optokens, string(c))
push!(tokens, Tokenized(startline, startcol, optokens[string(c)], nothing))
elseif haskey(symboltokens, string(c))
push!(tokens, Tokenized(startline, startcol, symboltokens[string(c)], nothing))
elseif isdigit(c)
integerstring = match(r"^\d+", line[startcol:end]).match
pastnumposition = startcol + length(integerstring)
if (pastnumposition <= length(line)) && isletter(line[pastnumposition])
throw("Tokenizer error line $startline: " * errors[8])
end
i = parse(Int, integerstring)
push!(tokens, Tokenized(startline, startcol, "Integer", i))
withintoken = length(integerstring) - 1
elseif c == Char(39) # single quote
if (m = match(r"([^\\\'\n]|\\n|\\\\)\'", line[startcol+1:end])) != nothing
chs = m.captures[1]
i = (chs == "\\n") ? Int('\n') : (chs == "\\\\" ? Int('\\') : Int(chs[1]))
push!(tokens, Tokenized(startline, startcol, "Integer", i))
withintoken = length(chs) + 1
else
println("line $startline: bad match with ", line[startcol+1:end])
end
elseif c == Char(34) # double quote
if (m = match(r"([^\"\n]+)\"", line[startcol+1:end])) == nothing
throw("Tokenizer error line $startline: $(errors[6])")
end
litstring = m.captures[1]
push!(tokens, Tokenized(startline, startcol, "String", "\"$litstring\""))
withintoken = length(litstring) + 1
elseif (cols = findfirst(r"[a-zA-Z]+", line[startcol:end])) != nothing
litstring = line[cols .+ startcol .- 1]
if haskey(keywordtokens, string(litstring))
push!(tokens, Tokenized(startline, startcol, keywordtokens[litstring], nothing))
else
litstring = match(r"[_a-zA-Z0-9]+", line[startcol:end]).match
push!(tokens, Tokenized(startline, startcol, "Identifier", string(litstring)))
end
withintoken = length(litstring) - 1
end
lastc = c
end
end
push!(tokens, Tokenized(length(lines), length(lines[end]) + 1, "End_of_input", nothing))
tokens
end
const test3txt = raw"""
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
"""
println("Line Col Name Value")
for tok in tokenize(test3txt)
println(lpad(tok.startline, 3), lpad(tok.startcol, 5), lpad(tok.name, 18), " ", tok.value != nothing ? tok.value : "")
end
|
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Global_Script | Global Script | λ 'as. impmapM (λ 'a. print qq{Argument: §(a)\n}) as |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Go | Go |
package main
import (
"fmt"
"os"
)
func main() {
for i, x := range os.Args[1:] {
fmt.Printf("the argument #%d is %s\n", i, x)
}
}
|
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Groovy | Groovy | println args |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #COBOL | COBOL | * an asterisk in 7th column comments the line out |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #CoffeeScript | CoffeeScript | # one line comment
### multi
line
comment ### |
http://rosettacode.org/wiki/Conway%27s_Game_of_Life | Conway's Game of Life | The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 when alive, or 0 when dead, in an m-by-m (or m×m) square array of cells.
We calculate N - the sum of live cells in C's eight-location neighbourhood, then cell C is alive or dead in the next generation based on the following table:
C N new C
1 0,1 -> 0 # Lonely
1 4,5,6,7,8 -> 0 # Overcrowded
1 2,3 -> 1 # Lives
0 3 -> 1 # It takes three to give birth!
0 0,1,2,4,5,6,7,8 -> 0 # Barren
Assume cells beyond the boundary are always dead.
The "game" is actually a zero-player game, meaning that its evolution is determined by its initial state, needing no input from human players. One interacts with the Game of Life by creating an initial configuration and observing how it evolves.
Task
Although you should test your implementation on more complex examples such as the glider in a larger universe, show the action of the blinker (three adjoining cells in a row all alive), over three generations, in a 3 by 3 grid.
References
Its creator John Conway, explains the game of life. Video from numberphile on youtube.
John Conway Inventing Game of Life - Numberphile video.
Related task
Langton's ant - another well known cellular automaton.
| #Go | Go | package main
import (
"bytes"
"fmt"
"math/rand"
"time"
)
type Field struct {
s [][]bool
w, h int
}
func NewField(w, h int) Field {
s := make([][]bool, h)
for i := range s {
s[i] = make([]bool, w)
}
return Field{s: s, w: w, h: h}
}
func (f Field) Set(x, y int, b bool) {
f.s[y][x] = b
}
func (f Field) Next(x, y int) bool {
on := 0
for i := -1; i <= 1; i++ {
for j := -1; j <= 1; j++ {
if f.State(x+i, y+j) && !(j == 0 && i == 0) {
on++
}
}
}
return on == 3 || on == 2 && f.State(x, y)
}
func (f Field) State(x, y int) bool {
for y < 0 {
y += f.h
}
for x < 0 {
x += f.w
}
return f.s[y%f.h][x%f.w]
}
type Life struct {
w, h int
a, b Field
}
func NewLife(w, h int) *Life {
a := NewField(w, h)
for i := 0; i < (w * h / 2); i++ {
a.Set(rand.Intn(w), rand.Intn(h), true)
}
return &Life{
a: a,
b: NewField(w, h),
w: w, h: h,
}
}
func (l *Life) Step() {
for y := 0; y < l.h; y++ {
for x := 0; x < l.w; x++ {
l.b.Set(x, y, l.a.Next(x, y))
}
}
l.a, l.b = l.b, l.a
}
func (l *Life) String() string {
var buf bytes.Buffer
for y := 0; y < l.h; y++ {
for x := 0; x < l.w; x++ {
b := byte(' ')
if l.a.State(x, y) {
b = '*'
}
buf.WriteByte(b)
}
buf.WriteByte('\n')
}
return buf.String()
}
func main() {
l := NewLife(80, 15)
for i := 0; i < 300; i++ {
l.Step()
fmt.Print("\x0c")
fmt.Println(l)
time.Sleep(time.Second / 30)
}
} |
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include if-then-else and switch.
Less common are arithmetic if, ternary operator and Hash-based conditionals.
Arithmetic if allows tight control over computed gotos, which optimizers have a hard time to figure out.
| #COBOL | COBOL | if condition-1
imperative-statement-1
else
imperative-statement-2
end-if
if condition-1
if condition-a
imperative-statement-1a
else
imperative-statement-1
end-if
else
if condition-a
imperative-statement-2a
else
imperative-statement-2
end-if
end-if |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #NetRexx | NetRexx | /* NetRexx */
options replace format comments java crossref symbols nobinary
runSample(arg)
return
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
method isEqual(list = Rexx[]) public static binary returns boolean
state = boolean (1 == 1) -- default to true
loop ix = 1 while ix < list.length
state = list[ix - 1] == list[ix]
if \state then leave ix
end ix
return state
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
method isAscending(list = Rexx[]) public static binary returns boolean
state = boolean (1 == 1) -- default to true
loop ix = 1 while ix < list.length
state = list[ix - 1] << list[ix]
if \state then leave ix
end ix
return state
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
method runSample(arg) private static
samples = [ -
['AA', 'BB', 'CC'] -
, ['AA', 'AA', 'AA'] -
, ['AA', 'CC', 'BB'] -
, ['single_element'] -
]
loop ix = 0 while ix < samples.length
sample = samples[ix]
if isEqual(sample) then eq = 'elements are identical'
else eq = 'elements are not identical'
if isAscending(sample) then asc = 'elements are in ascending order'
else asc = 'elements are not in ascending order'
say 'List:' Arrays.toString(sample)
say ' 'eq
say ' 'asc
end ix
return
|
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #F.23 | F# | let quibble list =
let rec inner = function
| [] -> ""
| [x] -> x
| [x;y] -> sprintf "%s and %s" x y
| h::t -> sprintf "%s, %s" h (inner t)
sprintf "{%s}" (inner list)
// test interactively
quibble []
quibble ["ABC"]
quibble ["ABC"; "DEF"]
quibble ["ABC"; "DEF"; "G"]
quibble ["ABC"; "DEF"; "G"; "H"] |
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Kotlin | Kotlin | // version 1.0.6
class CombsWithReps<T>(val m: Int, val n: Int, val items: List<T>, val countOnly: Boolean = false) {
private val combination = IntArray(m)
private var count = 0
init {
generate(0)
if (!countOnly) println()
println("There are $count combinations of $n things taken $m at a time, with repetitions")
}
private fun generate(k: Int) {
if (k >= m) {
if (!countOnly) {
for (i in 0 until m) print("${items[combination[i]]}\t")
println()
}
count++
}
else {
for (j in 0 until n)
if (k == 0 || j >= combination[k - 1]) {
combination[k] = j
generate(k + 1)
}
}
}
}
fun main(args: Array<String>) {
val doughnuts = listOf("iced", "jam", "plain")
CombsWithReps(2, 3, doughnuts)
println()
val generic10 = "0123456789".chunked(1)
CombsWithReps(3, 10, generic10, true)
} |
http://rosettacode.org/wiki/Combinations_and_permutations | Combinations and permutations |
This page uses content from Wikipedia. The original article was at Combination. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
This page uses content from Wikipedia. The original article was at Permutation. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Implement the combination (nCk) and permutation (nPk) operators in the target language:
n
C
k
=
(
n
k
)
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle ^{n}\operatorname {C} _{k}={\binom {n}{k}}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
See the Wikipedia articles for a more detailed description.
To test, generate and print examples of:
A sample of permutations from 1 to 12 and Combinations from 10 to 60 using exact Integer arithmetic.
A sample of permutations from 5 to 15000 and Combinations from 100 to 1000 using approximate Floating point arithmetic.
This 'floating point' code could be implemented using an approximation, e.g., by calling the Gamma function.
Related task
Evaluate binomial coefficients
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #REXX | REXX | /*REXX program compute and displays a sampling of combinations and permutations. */
numeric digits 100 /*use 100 decimal digits of precision. */
do j=1 for 12; _= /*show all permutations from 1 ──► 12.*/
do k=1 for j /*step through all J permutations. */
_=_ 'P('j","k')='perm(j,k)" " /*add an extra blank between numbers. */
end /*k*/
say strip(_) /*show the permutations horizontally. */
end /*j*/
say /*display a blank line for readability.*/
do j=10 to 60 by 10; _= /*show some combinations 10 ──► 60. */
do k= 1 to j by j%5 /*step through some combinations. */
_=_ 'C('j","k')='comb(j,k)" " /*add an extra blank between numbers. */
end /*k*/
say strip(_) /*show the combinations horizontally. */
end /*j*/
say /*display a blank line for readability.*/
numeric digits 20 /*force floating point for big numbers.*/
do j=5 to 15000 by 1000; _= /*show a few permutations, big numbers.*/
do k=1 to j for 5 by j%10 /*step through some J permutations. */
_=_ 'P('j","k')='perm(j,k)" " /*add an extra blank between numbers. */
end /*k*/
say strip(_) /*show the permutations horizontally. */
end /*j*/
say /*display a blank line for readability.*/
do j=100 to 1000 by 100; _= /*show a few combinations, big numbers.*/
do k= 1 to j by j%5 /*step through some combinations. */
_=_ 'C('j","k')='comb(j,k)" " /*add an extra blank between numbers. */
end /*k*/
say strip(_) /*show the combinations horizontally. */
end /*j*/
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
perm: procedure; parse arg x,y; call .combPerm; return _
.combPerm: _=1; do j=x-y+1 to x; _=_*j; end; return _
!: procedure; parse arg x; !=1; do j=2 to x; !=!*j; end; return !
/*──────────────────────────────────────────────────────────────────────────────────────*/
comb: procedure; parse arg x,y /*arguments: X things, Y at-a-time.*/
if y >x then return 0 /*oops-say, an error, too big a chunk.*/
if x =y then return 1 /*X things are the same as chunk size.*/
if x-y <y then y=x - y /*switch things around for speed. */
call .combPerm /*call subroutine to do heavy lifting. */
return _ / !(y) /*just perform one last division. */ |
http://rosettacode.org/wiki/Compiler/lexical_analyzer | Compiler/lexical analyzer | Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer, or scanner (though "scanner" is also used to refer to the first stage of a lexer).
Task[edit]
Create a lexical analyzer for the simple programming language specified below. The
program should read input from a file and/or stdin, and write output to a file and/or
stdout. If the language being used has a lexer module/library/class, it would be great
if two versions of the solution are provided: One without the lexer module, and one with.
Input Specification
The simple programming language to be analyzed is more or less a subset of C. It supports the following tokens:
Operators
Name
Common name
Character sequence
Op_multiply
multiply
*
Op_divide
divide
/
Op_mod
mod
%
Op_add
plus
+
Op_subtract
minus
-
Op_negate
unary minus
-
Op_less
less than
<
Op_lessequal
less than or equal
<=
Op_greater
greater than
>
Op_greaterequal
greater than or equal
>=
Op_equal
equal
==
Op_notequal
not equal
!=
Op_not
unary not
!
Op_assign
assignment
=
Op_and
logical and
&&
Op_or
logical or
¦¦
The - token should always be interpreted as Op_subtract by the lexer. Turning some Op_subtract into Op_negate will be the job of the syntax analyzer, which is not part of this task.
Symbols
Name
Common name
Character
LeftParen
left parenthesis
(
RightParen
right parenthesis
)
LeftBrace
left brace
{
RightBrace
right brace
}
Semicolon
semi-colon
;
Comma
comma
,
Keywords
Name
Character sequence
Keyword_if
if
Keyword_else
else
Keyword_while
while
Keyword_print
print
Keyword_putc
putc
Identifiers and literals
These differ from the the previous tokens, in that each occurrence of them has a value associated with it.
Name
Common name
Format description
Format regex
Value
Identifier
identifier
one or more letter/number/underscore characters, but not starting with a number
[_a-zA-Z][_a-zA-Z0-9]*
as is
Integer
integer literal
one or more digits
[0-9]+
as is, interpreted as a number
Integer
char literal
exactly one character (anything except newline or single quote) or one of the allowed escape sequences, enclosed by single quotes
'([^'\n]|\\n|\\\\)'
the ASCII code point number of the character, e.g. 65 for 'A' and 10 for '\n'
String
string literal
zero or more characters (anything except newline or double quote), enclosed by double quotes
"[^"\n]*"
the characters without the double quotes and with escape sequences converted
For char and string literals, the \n escape sequence is supported to represent a new-line character.
For char and string literals, to represent a backslash, use \\.
No other special sequences are supported. This means that:
Char literals cannot represent a single quote character (value 39).
String literals cannot represent strings containing double quote characters.
Zero-width tokens
Name
Location
End_of_input
when the end of the input stream is reached
White space
Zero or more whitespace characters, or comments enclosed in /* ... */, are allowed between any two tokens, with the exceptions noted below.
"Longest token matching" is used to resolve conflicts (e.g., in order to match <= as a single token rather than the two tokens < and =).
Whitespace is required between two tokens that have an alphanumeric character or underscore at the edge.
This means: keywords, identifiers, and integer literals.
e.g. ifprint is recognized as an identifier, instead of the keywords if and print.
e.g. 42fred is invalid, and neither recognized as a number nor an identifier.
Whitespace is not allowed inside of tokens (except for chars and strings where they are part of the value).
e.g. & & is invalid, and not interpreted as the && operator.
For example, the following two program fragments are equivalent, and should produce the same token stream except for the line and column positions:
if ( p /* meaning n is prime */ ) {
print ( n , " " ) ;
count = count + 1 ; /* number of primes found so far */
}
if(p){print(n," ");count=count+1;}
Complete list of token names
End_of_input Op_multiply Op_divide Op_mod Op_add Op_subtract
Op_negate Op_not Op_less Op_lessequal Op_greater Op_greaterequal
Op_equal Op_notequal Op_assign Op_and Op_or Keyword_if
Keyword_else Keyword_while Keyword_print Keyword_putc LeftParen RightParen
LeftBrace RightBrace Semicolon Comma Identifier Integer
String
Output Format
The program output should be a sequence of lines, each consisting of the following whitespace-separated fields:
the line number where the token starts
the column number where the token starts
the token name
the token value (only for Identifier, Integer, and String tokens)
the number of spaces between fields is up to you. Neatly aligned is nice, but not a requirement.
This task is intended to be used as part of a pipeline, with the other compiler tasks - for example:
lex < hello.t | parse | gen | vm
Or possibly:
lex hello.t lex.out
parse lex.out parse.out
gen parse.out gen.out
vm gen.out
This implies that the output of this task (the lexical analyzer) should be suitable as input to any of the Syntax Analyzer task programs.
Diagnostics
The following error conditions should be caught:
Error
Example
Empty character constant
''
Unknown escape sequence.
\r
Multi-character constant.
'xx'
End-of-file in comment. Closing comment characters not found.
End-of-file while scanning string literal. Closing string character not found.
End-of-line while scanning string literal. Closing string character not found before end-of-line.
Unrecognized character.
|
Invalid number. Starts like a number, but ends in non-numeric characters.
123abc
Test Cases
Input
Output
Test Case 1:
/*
Hello world
*/
print("Hello, World!\n");
4 1 Keyword_print
4 6 LeftParen
4 7 String "Hello, World!\n"
4 24 RightParen
4 25 Semicolon
5 1 End_of_input
Test Case 2:
/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");
4 1 Identifier phoenix_number
4 16 Op_assign
4 18 Integer 142857
4 24 Semicolon
5 1 Keyword_print
5 6 LeftParen
5 7 Identifier phoenix_number
5 21 Comma
5 23 String "\n"
5 27 RightParen
5 28 Semicolon
6 1 End_of_input
Test Case 3:
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
5 16 Keyword_print
5 40 Op_subtract
6 16 Keyword_putc
6 40 Op_less
7 16 Keyword_if
7 40 Op_greater
8 16 Keyword_else
8 40 Op_lessequal
9 16 Keyword_while
9 40 Op_greaterequal
10 16 LeftBrace
10 40 Op_equal
11 16 RightBrace
11 40 Op_notequal
12 16 LeftParen
12 40 Op_and
13 16 RightParen
13 40 Op_or
14 16 Op_subtract
14 40 Semicolon
15 16 Op_not
15 40 Comma
16 16 Op_multiply
16 40 Op_assign
17 16 Op_divide
17 40 Integer 42
18 16 Op_mod
18 40 String "String literal"
19 16 Op_add
19 40 Identifier variable_name
20 26 Integer 10
21 26 Integer 92
22 26 Integer 32
23 1 End_of_input
Test Case 4:
/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");
2 1 Keyword_print
2 6 LeftParen
2 7 Integer 42
2 9 RightParen
2 10 Semicolon
3 1 Keyword_print
3 6 LeftParen
3 7 String "\nHello World\nGood Bye\nok\n"
3 38 RightParen
3 39 Semicolon
4 1 Keyword_print
4 6 LeftParen
4 7 String "Print a slash n - \\n.\n"
4 33 RightParen
4 34 Semicolon
5 1 End_of_input
Additional examples
Your solution should pass all the test cases above and the additional tests found Here.
Reference
The C and Python versions can be considered reference implementations.
Related Tasks
Syntax Analyzer task
Code Generator task
Virtual Machine Interpreter task
AST Interpreter task
| #kotlin | kotlin | // Input: command line argument of file to process or console input. A two or
// three character console input of digits followed by a new line will be
// checked for an integer between zero and twenty-five to select a fixed test
// case to run. Any other console input will be parsed.
// Code based on the Java version found here:
// https://rosettacode.org/mw/index.php?title=Compiler/lexical_analyzer&action=edit§ion=22
// Class to halt the parsing with an exception.
class ParsingFailed(message: String): Exception(message)
// Enumerate class of tokens supported by this scanner.
enum class TokenType {
Tk_End_of_input, Op_multiply, Op_divide, Op_mod, Op_add, Op_subtract,
Op_negate, Op_not, Op_less, Op_lessequal, Op_greater, Op_greaterequal,
Op_equal, Op_notequal, Op_assign, Op_and, Op_or, Kw_if,
Kw_else, Kw_while, Kw_print, Kw_putc, Sy_LeftParen, Sy_RightParen,
Sy_LeftBrace, Sy_RightBrace, Sy_Semicolon, Sy_Comma, Tk_Identifier,
Tk_Integer, Tk_String;
override fun toString() =
listOf("End_of_input", "Op_multiply", "Op_divide", "Op_mod", "Op_add",
"Op_subtract", "Op_negate", "Op_not", "Op_less", "Op_lessequal",
"Op_greater", "Op_greaterequal", "Op_equal", "Op_notequal",
"Op_assign", "Op_and", "Op_or", "Keyword_if", "Keyword_else",
"Keyword_while", "Keyword_print", "Keyword_putc", "LeftParen",
"RightParen", "LeftBrace", "RightBrace", "Semicolon", "Comma",
"Identifier", "Integer", "String")[this.ordinal]
} // TokenType
// Data class of tokens returned by the scanner.
data class Token(val token: TokenType, val value: String, val line: Int,
val pos: Int) {
// Overridden method to display the token.
override fun toString() =
"%5d %5d %-15s %s".format(line, pos, this.token,
when (this.token) {
TokenType.Tk_Integer, TokenType.Tk_Identifier ->
" %s".format(this.value)
TokenType.Tk_String ->
this.value.toList().joinToString("", " \"", "\"") {
when (it) {
'\t' ->
"\\t"
'\n' ->
"\\n"
'\u000b' ->
"\\v"
'\u000c' ->
"\\f"
'\r' ->
"\\r"
'"' ->
"\\\""
'\\' ->
"\\"
in ' '..'~' ->
"$it"
else ->
"\\u%04x".format(it.code) } }
else ->
"" } )
} // Token
// Function to display an error message and halt the scanner.
fun error(line: Int, pos: Int, msg: String): Nothing =
throw ParsingFailed("(%d, %d) %s\n".format(line, pos, msg))
// Class to process the source into tokens with properties of the
// source string, the line number, the column position, the index
// within the source string, the current character being processed,
// and map of the keyword strings to the corresponding token type.
class Lexer(private val s: String) {
private var line = 1
private var pos = 1
private var position = 0
private var chr =
if (s.isEmpty())
' '
else
s[0]
private val keywords = mapOf<String, TokenType>(
"if" to TokenType.Kw_if,
"else" to TokenType.Kw_else,
"print" to TokenType.Kw_print,
"putc" to TokenType.Kw_putc,
"while" to TokenType.Kw_while)
// Method to retrive the next character from the source. Use null after
// the end of our source.
private fun getNextChar() =
if (++this.position >= this.s.length) {
this.pos++
this.chr = '\u0000'
this.chr
} else {
this.pos++
this.chr = this.s[this.position]
when (this.chr) {
'\n' -> {
this.line++
this.pos = 0
} // line
'\t' ->
while (this.pos%8 != 1)
this.pos++
} // when
this.chr
} // if
// Method to return the division token, skip the comment, or handle the
// error.
private fun div_or_comment(line: Int, pos: Int): Token =
if (getNextChar() != '*')
Token(TokenType.Op_divide, "", line, pos);
else {
getNextChar() // Skip comment start
outer@
while (true)
when (this.chr) {
'\u0000' ->
error(line, pos, "Lexer: EOF in comment");
'*' ->
if (getNextChar() == '/') {
getNextChar() // Skip comment end
break@outer
} // if
else ->
getNextChar()
} // when
getToken()
} // if
// Method to verify a character literal. Return the token or handle the
// error.
private fun char_lit(line: Int, pos: Int): Token {
var c = getNextChar() // skip opening quote
when (c) {
'\'' ->
error(line, pos, "Lexer: Empty character constant");
'\\' ->
c = when (getNextChar()) {
'n' ->
10.toChar()
'\\' ->
'\\'
'\'' ->
'\''
else ->
error(line, pos, "Lexer: Unknown escape sequence '\\%c'".
format(this.chr)) }
} // when
if (getNextChar() != '\'')
error(line, pos, "Lexer: Multi-character constant")
getNextChar() // Skip closing quote
return Token(TokenType.Tk_Integer, c.code.toString(), line, pos)
} // char_lit
// Method to check next character to see whether it belongs to the token
// we might be in the middle of. Return the correct token or handle the
// error.
private fun follow(expect: Char, ifyes: TokenType, ifno: TokenType,
line: Int, pos: Int): Token =
when {
getNextChar() == expect -> {
getNextChar()
Token(ifyes, "", line, pos)
} // matches
ifno == TokenType.Tk_End_of_input ->
error(line, pos,
"Lexer: %c expected: (%d) '%c'".format(expect,
this.chr.code, this.chr))
else ->
Token(ifno, "", line, pos)
} // when
// Method to verify a character string. Return the token or handle the
// error.
private fun string_lit(start: Char, line: Int, pos: Int): Token {
var result = ""
while (getNextChar() != start)
when (this.chr) {
'\u0000' ->
error(line, pos, "Lexer: EOF while scanning string literal")
'\n' ->
error(line, pos, "Lexer: EOL while scanning string literal")
'\\' ->
when (getNextChar()) {
'\\' ->
result += '\\'
'n' ->
result += '\n'
'"' ->
result += '"'
else ->
error(line, pos, "Lexer: Escape sequence unknown '\\%c'".
format(this.chr))
} // when
else ->
result += this.chr
} // when
getNextChar() // Toss closing quote
return Token(TokenType.Tk_String, result, line, pos)
} // string_lit
// Method to retrive an identifier or integer. Return the keyword
// token, if the string matches one. Return the integer token,
// if the string is all digits. Return the identifer token, if the
// string is valid. Otherwise, handle the error.
private fun identifier_or_integer(line: Int, pos: Int): Token {
var is_number = true
var text = ""
while (this.chr in listOf('_')+('0'..'9')+('a'..'z')+('A'..'Z')) {
text += this.chr
is_number = is_number && this.chr in '0'..'9'
getNextChar()
} // while
if (text.isEmpty())
error(line, pos, "Lexer: Unrecognized character: (%d) %c".
format(this.chr.code, this.chr))
return when {
text[0] in '0'..'9' ->
if (!is_number)
error(line, pos, "Lexer: Invalid number: %s".
format(text))
else {
val max = Int.MAX_VALUE.toString()
if (text.length > max.length || (text.length == max.length &&
max < text))
error(line, pos,
"Lexer: Number exceeds maximum value %s".
format(text))
Token(TokenType.Tk_Integer, text, line, pos)
} // if
this.keywords.containsKey(text) ->
Token(this.keywords[text]!!, "", line, pos)
else ->
Token(TokenType.Tk_Identifier, text, line, pos) }
} // identifier_or_integer
// Method to skip whitespace both C's and Unicode ones and retrive the next
// token.
private fun getToken(): Token {
while (this.chr in listOf('\t', '\n', '\u000b', '\u000c', '\r', ' ') ||
this.chr.isWhitespace())
getNextChar()
val line = this.line
val pos = this.pos
return when (this.chr) {
'\u0000' ->
Token(TokenType.Tk_End_of_input, "", line, pos)
'/' ->
div_or_comment(line, pos)
'\'' ->
char_lit(line, pos)
'<' ->
follow('=', TokenType.Op_lessequal, TokenType.Op_less, line, pos)
'>' ->
follow('=', TokenType.Op_greaterequal, TokenType.Op_greater, line, pos)
'=' ->
follow('=', TokenType.Op_equal, TokenType.Op_assign, line, pos)
'!' ->
follow('=', TokenType.Op_notequal, TokenType.Op_not, line, pos)
'&' ->
follow('&', TokenType.Op_and, TokenType.Tk_End_of_input, line, pos)
'|' ->
follow('|', TokenType.Op_or, TokenType.Tk_End_of_input, line, pos)
'"' ->
string_lit(this.chr, line, pos)
'{' -> {
getNextChar()
Token(TokenType.Sy_LeftBrace, "", line, pos)
} // open brace
'}' -> {
getNextChar()
Token(TokenType.Sy_RightBrace, "", line, pos)
} // close brace
'(' -> {
getNextChar()
Token(TokenType.Sy_LeftParen, "", line, pos)
} // open paren
')' -> {
getNextChar()
Token(TokenType.Sy_RightParen, "", line, pos)
} // close paren
'+' -> {
getNextChar()
Token(TokenType.Op_add, "", line, pos)
} // plus
'-' -> {
getNextChar()
Token(TokenType.Op_subtract, "", line, pos)
} // dash
'*' -> {
getNextChar()
Token(TokenType.Op_multiply, "", line, pos)
} // asterisk
'%' -> {
getNextChar()
Token(TokenType.Op_mod, "", line, pos)
} // percent
';' -> {
getNextChar()
Token(TokenType.Sy_Semicolon, "", line, pos)
} // semicolon
',' -> {
getNextChar()
Token(TokenType.Sy_Comma, "", line, pos)
} // comma
else ->
identifier_or_integer(line, pos) }
} // getToken
// Method to parse and display tokens.
fun printTokens() {
do {
val t: Token = getToken()
println(t)
} while (t.token != TokenType.Tk_End_of_input)
} // printTokens
} // Lexer
// Function to test all good tests from the website and produce all of the
// error messages this program supports.
fun tests(number: Int) {
// Function to generate test case 0 source: Hello World/Text.
fun hello() {
Lexer(
"""/*
Hello world
*/
print("Hello, World!\n");
""").printTokens()
} // hello
// Function to generate test case 1 source: Phoenix Number.
fun phoenix() {
Lexer(
"""/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");""").printTokens()
} // phoenix
// Function to generate test case 2 source: All Symbols.
fun symbols() {
Lexer(
"""/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '""").printTokens()
} // symbols
// Function to generate test case 3 source: Test Case 4.
fun four() {
Lexer(
"""/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");""").printTokens()
} // four
// Function to generate test case 4 source: Count.
fun count() {
Lexer(
"""count = 1;
while (count < 10) {
print("count is: ", count, "\n");
count = count + 1;
}""").printTokens()
} // count
// Function to generate test case 5 source: 100 Doors.
fun doors() {
Lexer(
"""/* 100 Doors */
i = 1;
while (i * i <= 100) {
print("door ", i * i, " is open\n");
i = i + 1;
}""").printTokens()
} // doors
// Function to generate test case 6 source: Negative Tests.
fun negative() {
Lexer(
"""a = (-1 * ((-1 * (5 * 15)) / 10));
print(a, "\n");
b = -a;
print(b, "\n");
print(-b, "\n");
print(-(1), "\n");""").printTokens()
} // negative
// Function to generate test case 7 source: Deep.
fun deep() {
Lexer(
"""print(---------------------------------+++5, "\n");
print(((((((((3 + 2) * ((((((2))))))))))))), "\n");
if (1) { if (1) { if (1) { if (1) { if (1) { print(15, "\n"); } } } } }""").printTokens()
} // deep
// Function to generate test case 8 source: Greatest Common Divisor.
fun gcd() {
Lexer(
"""/* Compute the gcd of 1071, 1029: 21 */
a = 1071;
b = 1029;
while (b != 0) {
new_a = b;
b = a % b;
a = new_a;
}
print(a);""").printTokens()
} // gcd
// Function to generate test case 9 source: Factorial.
fun factorial() {
Lexer(
"""/* 12 factorial is 479001600 */
n = 12;
result = 1;
i = 1;
while (i <= n) {
result = result * i;
i = i + 1;
}
print(result);""").printTokens()
} // factorial
// Function to generate test case 10 source: Fibonacci Sequence.
fun fibonacci() {
Lexer(
"""/* fibonacci of 44 is 701408733 */
n = 44;
i = 1;
a = 0;
b = 1;
while (i < n) {
w = a + b;
a = b;
b = w;
i = i + 1;
}
print(w, "\n");""").printTokens()
} // fibonacci
// Function to generate test case 11 source: FizzBuzz.
fun fizzbuzz() {
Lexer(
"""/* FizzBuzz */
i = 1;
while (i <= 100) {
if (!(i % 15))
print("FizzBuzz");
else if (!(i % 3))
print("Fizz");
else if (!(i % 5))
print("Buzz");
else
print(i);
print("\n");
i = i + 1;
}""").printTokens()
} // fizzbuzz
// Function to generate test case 12 source: 99 Bottles of Beer.
fun bottles() {
Lexer(
"""/* 99 bottles */
bottles = 99;
while (bottles > 0) {
print(bottles, " bottles of beer on the wall\n");
print(bottles, " bottles of beer\n");
print("Take one down, pass it around\n");
bottles = bottles - 1;
print(bottles, " bottles of beer on the wall\n\n");
}""").printTokens()
} // bottles
// Function to generate test case 13 source: Primes.
fun primes() {
Lexer(
"""/*
Simple prime number generator
*/
count = 1;
n = 1;
limit = 100;
while (n < limit) {
k=3;
p=1;
n=n+2;
while ((k*k<=n) && (p)) {
p=n/k*k!=n;
k=k+2;
}
if (p) {
print(n, " is prime\n");
count = count + 1;
}
}
print("Total primes found: ", count, "\n");""").printTokens()
} // primes
// Function to generate test case 14 source: Ascii Mandelbrot.
fun ascii() {
Lexer(
"""{
/*
This is an integer ascii Mandelbrot generator
*/
left_edge = -420;
right_edge = 300;
top_edge = 300;
bottom_edge = -300;
x_step = 7;
y_step = 15;
max_iter = 200;
y0 = top_edge;
while (y0 > bottom_edge) {
x0 = left_edge;
while (x0 < right_edge) {
y = 0;
x = 0;
the_char = ' ';
i = 0;
while (i < max_iter) {
x_x = (x * x) / 200;
y_y = (y * y) / 200;
if (x_x + y_y > 800 ) {
the_char = '0' + i;
if (i > 9) {
the_char = '@';
}
i = max_iter;
}
y = x * y / 100 + y0;
x = x_x - y_y + x0;
i = i + 1;
}
putc(the_char);
x0 = x0 + x_step;
}
putc('\n');
y0 = y0 - y_step;
}
}
""").printTokens()
} // ascii
when (number) {
0 ->
hello()
1 ->
phoenix()
2 ->
symbols()
3 ->
four()
4 ->
count()
5 ->
doors()
6 ->
negative()
7 ->
deep()
8 ->
gcd()
9 ->
factorial()
10 ->
fibonacci()
11 ->
fizzbuzz()
12 ->
bottles()
13 ->
primes()
14 ->
ascii()
15 -> // Lexer: Empty character constant
Lexer("''").printTokens()
16 -> // Lexer: Unknown escape sequence
Lexer("'\\x").printTokens()
17 -> // Lexer: Multi-character constant
Lexer("' ").printTokens()
18 -> // Lexer: EOF in comment
Lexer("/*").printTokens()
19 -> // Lexer: EOL in string
Lexer("\"\n").printTokens()
20 -> // Lexer: EOF in string
Lexer("\"").printTokens()
21 -> // Lexer: Escape sequence unknown
Lexer("\"\\x").printTokens()
22 -> // Lexer: Unrecognized character
Lexer("~").printTokens()
23 -> // Lexer: invalid number
Lexer("9a9").printTokens()
24 -> // Lexer: Number exceeds maximum value
Lexer("2147483648\n9223372036854775808").printTokens()
25 -> // Lexer: Operator expected
Lexer("|.").printTokens()
else ->
println("Invalid test number %d!".format(number))
} // when
} // tests
// Main function to check our source and read its data before parsing it.
// With no source specified, run the test of all symbols.
fun main(args: Array<String>) {
try {
val s =
if (args.size > 0 && args[0].isNotEmpty()) // file on command line
java.util.Scanner(java.io.File(args[0]))
else // use the console
java.util.Scanner(System.`in`)
var source = ""
while (s.hasNext())
source += s.nextLine()+
if (s.hasNext())
"\n"
else
""
if (args.size > 0 && args[0].isNotEmpty()) // file on command line
Lexer(source).printTokens()
else {
val digits = source.filter { it in '0'..'9' }
when {
source.isEmpty() -> // nothing given
tests(2)
source.length in 1..2 && digits.length == source.length &&
digits.toInt() in 0..25 ->
tests(digits.toInt())
else ->
Lexer(source).printTokens()
} // when
} // if
} catch(e: Throwable) {
println(e.message)
System.exit(1)
} // try
} // main |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Harbour | Harbour | PROCEDURE Main()
LOCAL i
FOR i := 1 TO PCount()
? "argument", hb_ntos( i ), "=", hb_PValue( i )
NEXT
RETURN |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Haskell | Haskell | import System
main = getArgs >>= print |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #ColdFusion | ColdFusion | As ColdFusion's grammar is based around HTML syntax, commenting is similar to HTML.
<!--- This is a comment. Nothing in this tag can be seen by the end user.
Note the three-or-greater dashes to open and close the tag. --->
<!-- This is an HTML comment. Any HTML between the opening and closing of the tag will be ignored, but any ColdFusion code will still run.
Note that in the popular FuseBox framework for ColdFusion, the circuit.xml files require that you use this style of comment. --> |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Common_Lisp | Common Lisp | ;;;; This code implements the foo and bar functions
;;; The foo function calls bar on the first argument and multiplies the result by the second.
;;; The arguments are two integers
(defun foo (a b)
;; Call bar and multiply
(* (bar a) ; Calling bar
b))
;;; The bar function simply adds 3 to the argument
(defun bar (n)
(+ n 3)) |
http://rosettacode.org/wiki/Conway%27s_Game_of_Life | Conway's Game of Life | The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 when alive, or 0 when dead, in an m-by-m (or m×m) square array of cells.
We calculate N - the sum of live cells in C's eight-location neighbourhood, then cell C is alive or dead in the next generation based on the following table:
C N new C
1 0,1 -> 0 # Lonely
1 4,5,6,7,8 -> 0 # Overcrowded
1 2,3 -> 1 # Lives
0 3 -> 1 # It takes three to give birth!
0 0,1,2,4,5,6,7,8 -> 0 # Barren
Assume cells beyond the boundary are always dead.
The "game" is actually a zero-player game, meaning that its evolution is determined by its initial state, needing no input from human players. One interacts with the Game of Life by creating an initial configuration and observing how it evolves.
Task
Although you should test your implementation on more complex examples such as the glider in a larger universe, show the action of the blinker (three adjoining cells in a row all alive), over three generations, in a 3 by 3 grid.
References
Its creator John Conway, explains the game of life. Video from numberphile on youtube.
John Conway Inventing Game of Life - Numberphile video.
Related task
Langton's ant - another well known cellular automaton.
| #Groovy | Groovy |
class GameOfLife {
int generations
int dimensions
def board
GameOfLife(generations = 5, dimensions = 5) {
this.generations = generations
this.dimensions = dimensions
this.board = createBlinkerBoard()
}
static def createBlinkerBoard() {
[
[].withDefault{0},
[0,0,1].withDefault{0},
[0,0,1].withDefault{0},
[0,0,1].withDefault{0}
].withDefault{[]}
}
static def createGliderBoard() {
[
[].withDefault{0},
[0,0,1].withDefault{0},
[0,0,0,1].withDefault{0},
[0,1,1,1].withDefault{0}
].withDefault{[]}
}
static def getValue(board, point) {
def x,y
(x,y) = point
if(x < 0 || y < 0) {
return 0
}
board[x][y] ? 1 : 0
}
static def countNeighbors(board, point) {
def x,y
(x,y) = point
def neighbors = 0
neighbors += getValue(board, [x-1,y-1])
neighbors += getValue(board, [x-1,y])
neighbors += getValue(board, [x-1,y+1])
neighbors += getValue(board, [x,y-1])
neighbors += getValue(board, [x,y+1])
neighbors += getValue(board, [x+1,y-1])
neighbors += getValue(board, [x+1,y])
neighbors += getValue(board, [x+1,y+1])
neighbors
}
static def conwaysRule(currentValue, neighbors) {
def newValue = 0
if(neighbors == 3 || (currentValue && neighbors == 2)) {
newValue = 1
}
newValue
}
static def createNextGeneration(currentBoard, dimensions) {
def newBoard = [].withDefault{[].withDefault{0}}
(0..(dimensions-1)).each { row ->
(0..(dimensions-1)).each { column ->
def point = [row, column]
def currentValue = getValue(currentBoard, point)
def neighbors = countNeighbors(currentBoard, point)
newBoard[row][column] = conwaysRule(currentValue, neighbors)
}
}
newBoard
}
static def printBoard(generationCount, board, dimensions) {
println "Generation ${generationCount}"
println '*' * 80
(0..(dimensions-1)).each { row ->
(0..(dimensions-1)).each { column ->
print board[row][column] ? 'X' : '.'
}
print System.getProperty('line.separator')
}
println ''
}
def start() {
(1..generations).each { generation ->
printBoard(generation, this.board, this.dimensions)
this.board = createNextGeneration(this.board, this.dimensions)
}
}
}
// Blinker
def game = new GameOfLife()
game.start()
// Glider
game = new GameOfLife(10, 10)
game.board = game.createGliderBoard()
game.start()
|
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include if-then-else and switch.
Less common are arithmetic if, ternary operator and Hash-based conditionals.
Arithmetic if allows tight control over computed gotos, which optimizers have a hard time to figure out.
| #CoffeeScript | CoffeeScript |
if n == 1
console.log "one"
else if n == 2
console.log "two"
else
console.log "other"
|
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #Nim | Nim |
func allEqual(s: openArray[string]): bool =
for i in 1..s.high:
if s[i] != s[0]:
return false
result = true
func ascending(s: openArray[string]): bool =
for i in 1..s.high:
if s[i] <= s[i - 1]:
return false
result = true
doAssert allEqual(["abc", "abc", "abc"])
doAssert not allEqual(["abc", "abd", "abc"])
doAssert ascending(["abc", "abd", "abe"])
doAssert not ascending(["abc", "abe", "abd"])
doAssert allEqual(["abc"])
doAssert ascending(["abc"]) |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #OCaml | OCaml |
open List;;
let analyze cmp l =
let rec analyze' l prevs =
match l with
[] -> true
| [s] -> cmp prevs s
| s::rest -> (cmp prevs s) && (analyze' rest s)
in analyze' (List.tl l) (List.hd l)
;;
let isEqual = analyze (=) ;;
let isAscending = analyze (<) ;;
let test sample =
List.iter print_endline sample;
if (isEqual sample)
then (print_endline "elements are identical")
else (print_endline "elements are not identical");
if (isAscending sample)
then print_endline "elements are in ascending order"
else print_endline "elements are not in ascending order";;
let lasc = ["AA";"BB";"CC";"EE"];;
let leq = ["AA";"AA";"AA";"AA"];;
let lnoasc = ["AA";"BB";"EE";"CC"];;
List.iter test [lasc;leq;lnoasc];;
|
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #Factor | Factor | USING: inverse qw sequences ;
: (quibble) ( seq -- seq' )
{
{ [ { } ] [ "" ] }
{ [ 1array ] [ ] }
{ [ 2array ] [ " and " glue ] }
[ unclip swap (quibble) ", " glue ]
} switch ;
: quibble ( seq -- str ) (quibble) "{%s}" sprintf ;
{ } qw{ ABC } qw{ ABC DEF } qw{ ABC DEF G H }
[ quibble print ] 4 napply |
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #Forth | Forth |
: read bl parse ;
: not-empty? ( c-addr u -- c-addr u true | false ) ?dup-if true else drop false then ;
: third-to-last 2rot ;
: second-to-last 2swap ;
: quibble
." {"
read read begin read not-empty? while third-to-last type ." , " repeat
second-to-last not-empty? if type then
not-empty? if ." and " type then
." }" cr ;
quibble
quibble ABC
quibble ABC DEF
quibble ABC DEF G H
|
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #LFE | LFE |
(defun combinations
(('() _)
'())
((coll 1)
(lists:map #'list/1 coll))
(((= (cons head tail) coll) n)
(++ (lc ((<- subcoll (combinations coll (- n 1))))
(cons head subcoll))
(combinations tail n))))
|
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Lobster | Lobster | import std
// set S of length n, choose k
def choose(s, k, f):
let got = map(k): s[0]
let n = s.length
def choosi(n_chosen, at):
var count = 0
if n_chosen == k:
f(got)
return 1
var i = at
while i < n:
got[n_chosen] = s[i]
count += choosi(n_chosen + 1, i)
i += 1
return count
return choosi(0, 0)
let count = choose(["iced", "jam", "plain"], 2): print(_)
print count
let extra = choose(map(10):_, 3): _
print extra |
http://rosettacode.org/wiki/Combinations_and_permutations | Combinations and permutations |
This page uses content from Wikipedia. The original article was at Combination. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
This page uses content from Wikipedia. The original article was at Permutation. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Implement the combination (nCk) and permutation (nPk) operators in the target language:
n
C
k
=
(
n
k
)
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle ^{n}\operatorname {C} _{k}={\binom {n}{k}}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
See the Wikipedia articles for a more detailed description.
To test, generate and print examples of:
A sample of permutations from 1 to 12 and Combinations from 10 to 60 using exact Integer arithmetic.
A sample of permutations from 5 to 15000 and Combinations from 100 to 1000 using approximate Floating point arithmetic.
This 'floating point' code could be implemented using an approximation, e.g., by calling the Gamma function.
Related task
Evaluate binomial coefficients
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Ruby | Ruby | include Math
class Integer
def permutation(k)
(self-k+1 .. self).inject( :*)
end
def combination(k)
self.permutation(k) / (1 .. k).inject( :*)
end
def big_permutation(k)
exp( lgamma_plus(self) - lgamma_plus(self -k))
end
def big_combination(k)
exp( lgamma_plus(self) - lgamma_plus(self - k) - lgamma_plus(k))
end
private
def lgamma_plus(n)
lgamma(n+1)[0] #lgamma is the natural log of gamma
end
end
p 12.permutation(9) #=> 79833600
p 12.big_permutation(9) #=> 79833600.00000021
p 60.combination(53) #=> 386206920
p 145.big_permutation(133) #=> 1.6801459655817956e+243
p 900.big_combination(450) #=> 2.247471882064647e+269
p 1000.big_combination(969) #=> 7.602322407770517e+58
p 15000.big_permutation(73) #=> 6.004137561717704e+304
#That's about the maximum of Float:
p 15000.big_permutation(74) #=> Infinity
#Fixnum has no maximum:
p 15000.permutation(74) #=> 896237613852967826239917238565433149353074416025197784301593335243699358040738127950872384197159884905490054194835376498534786047382445592358843238688903318467070575184552953997615178973027752714539513893159815472948987921587671399790410958903188816684444202526779550201576117111844818124800000000000000000000
|
http://rosettacode.org/wiki/Compiler/lexical_analyzer | Compiler/lexical analyzer | Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer, or scanner (though "scanner" is also used to refer to the first stage of a lexer).
Task[edit]
Create a lexical analyzer for the simple programming language specified below. The
program should read input from a file and/or stdin, and write output to a file and/or
stdout. If the language being used has a lexer module/library/class, it would be great
if two versions of the solution are provided: One without the lexer module, and one with.
Input Specification
The simple programming language to be analyzed is more or less a subset of C. It supports the following tokens:
Operators
Name
Common name
Character sequence
Op_multiply
multiply
*
Op_divide
divide
/
Op_mod
mod
%
Op_add
plus
+
Op_subtract
minus
-
Op_negate
unary minus
-
Op_less
less than
<
Op_lessequal
less than or equal
<=
Op_greater
greater than
>
Op_greaterequal
greater than or equal
>=
Op_equal
equal
==
Op_notequal
not equal
!=
Op_not
unary not
!
Op_assign
assignment
=
Op_and
logical and
&&
Op_or
logical or
¦¦
The - token should always be interpreted as Op_subtract by the lexer. Turning some Op_subtract into Op_negate will be the job of the syntax analyzer, which is not part of this task.
Symbols
Name
Common name
Character
LeftParen
left parenthesis
(
RightParen
right parenthesis
)
LeftBrace
left brace
{
RightBrace
right brace
}
Semicolon
semi-colon
;
Comma
comma
,
Keywords
Name
Character sequence
Keyword_if
if
Keyword_else
else
Keyword_while
while
Keyword_print
print
Keyword_putc
putc
Identifiers and literals
These differ from the the previous tokens, in that each occurrence of them has a value associated with it.
Name
Common name
Format description
Format regex
Value
Identifier
identifier
one or more letter/number/underscore characters, but not starting with a number
[_a-zA-Z][_a-zA-Z0-9]*
as is
Integer
integer literal
one or more digits
[0-9]+
as is, interpreted as a number
Integer
char literal
exactly one character (anything except newline or single quote) or one of the allowed escape sequences, enclosed by single quotes
'([^'\n]|\\n|\\\\)'
the ASCII code point number of the character, e.g. 65 for 'A' and 10 for '\n'
String
string literal
zero or more characters (anything except newline or double quote), enclosed by double quotes
"[^"\n]*"
the characters without the double quotes and with escape sequences converted
For char and string literals, the \n escape sequence is supported to represent a new-line character.
For char and string literals, to represent a backslash, use \\.
No other special sequences are supported. This means that:
Char literals cannot represent a single quote character (value 39).
String literals cannot represent strings containing double quote characters.
Zero-width tokens
Name
Location
End_of_input
when the end of the input stream is reached
White space
Zero or more whitespace characters, or comments enclosed in /* ... */, are allowed between any two tokens, with the exceptions noted below.
"Longest token matching" is used to resolve conflicts (e.g., in order to match <= as a single token rather than the two tokens < and =).
Whitespace is required between two tokens that have an alphanumeric character or underscore at the edge.
This means: keywords, identifiers, and integer literals.
e.g. ifprint is recognized as an identifier, instead of the keywords if and print.
e.g. 42fred is invalid, and neither recognized as a number nor an identifier.
Whitespace is not allowed inside of tokens (except for chars and strings where they are part of the value).
e.g. & & is invalid, and not interpreted as the && operator.
For example, the following two program fragments are equivalent, and should produce the same token stream except for the line and column positions:
if ( p /* meaning n is prime */ ) {
print ( n , " " ) ;
count = count + 1 ; /* number of primes found so far */
}
if(p){print(n," ");count=count+1;}
Complete list of token names
End_of_input Op_multiply Op_divide Op_mod Op_add Op_subtract
Op_negate Op_not Op_less Op_lessequal Op_greater Op_greaterequal
Op_equal Op_notequal Op_assign Op_and Op_or Keyword_if
Keyword_else Keyword_while Keyword_print Keyword_putc LeftParen RightParen
LeftBrace RightBrace Semicolon Comma Identifier Integer
String
Output Format
The program output should be a sequence of lines, each consisting of the following whitespace-separated fields:
the line number where the token starts
the column number where the token starts
the token name
the token value (only for Identifier, Integer, and String tokens)
the number of spaces between fields is up to you. Neatly aligned is nice, but not a requirement.
This task is intended to be used as part of a pipeline, with the other compiler tasks - for example:
lex < hello.t | parse | gen | vm
Or possibly:
lex hello.t lex.out
parse lex.out parse.out
gen parse.out gen.out
vm gen.out
This implies that the output of this task (the lexical analyzer) should be suitable as input to any of the Syntax Analyzer task programs.
Diagnostics
The following error conditions should be caught:
Error
Example
Empty character constant
''
Unknown escape sequence.
\r
Multi-character constant.
'xx'
End-of-file in comment. Closing comment characters not found.
End-of-file while scanning string literal. Closing string character not found.
End-of-line while scanning string literal. Closing string character not found before end-of-line.
Unrecognized character.
|
Invalid number. Starts like a number, but ends in non-numeric characters.
123abc
Test Cases
Input
Output
Test Case 1:
/*
Hello world
*/
print("Hello, World!\n");
4 1 Keyword_print
4 6 LeftParen
4 7 String "Hello, World!\n"
4 24 RightParen
4 25 Semicolon
5 1 End_of_input
Test Case 2:
/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");
4 1 Identifier phoenix_number
4 16 Op_assign
4 18 Integer 142857
4 24 Semicolon
5 1 Keyword_print
5 6 LeftParen
5 7 Identifier phoenix_number
5 21 Comma
5 23 String "\n"
5 27 RightParen
5 28 Semicolon
6 1 End_of_input
Test Case 3:
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
5 16 Keyword_print
5 40 Op_subtract
6 16 Keyword_putc
6 40 Op_less
7 16 Keyword_if
7 40 Op_greater
8 16 Keyword_else
8 40 Op_lessequal
9 16 Keyword_while
9 40 Op_greaterequal
10 16 LeftBrace
10 40 Op_equal
11 16 RightBrace
11 40 Op_notequal
12 16 LeftParen
12 40 Op_and
13 16 RightParen
13 40 Op_or
14 16 Op_subtract
14 40 Semicolon
15 16 Op_not
15 40 Comma
16 16 Op_multiply
16 40 Op_assign
17 16 Op_divide
17 40 Integer 42
18 16 Op_mod
18 40 String "String literal"
19 16 Op_add
19 40 Identifier variable_name
20 26 Integer 10
21 26 Integer 92
22 26 Integer 32
23 1 End_of_input
Test Case 4:
/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");
2 1 Keyword_print
2 6 LeftParen
2 7 Integer 42
2 9 RightParen
2 10 Semicolon
3 1 Keyword_print
3 6 LeftParen
3 7 String "\nHello World\nGood Bye\nok\n"
3 38 RightParen
3 39 Semicolon
4 1 Keyword_print
4 6 LeftParen
4 7 String "Print a slash n - \\n.\n"
4 33 RightParen
4 34 Semicolon
5 1 End_of_input
Additional examples
Your solution should pass all the test cases above and the additional tests found Here.
Reference
The C and Python versions can be considered reference implementations.
Related Tasks
Syntax Analyzer task
Code Generator task
Virtual Machine Interpreter task
AST Interpreter task
| #Lua | Lua | -- module token_name (in a file "token_name.lua")
local token_name = {
['*'] = 'Op_multiply',
['/'] = 'Op_divide',
['%'] = 'Op_mod',
['+'] = 'Op_add',
['-'] = 'Op_subtract',
['<'] = 'Op_less',
['<='] = 'Op_lessequal',
['>'] = 'Op_greater',
['>='] = 'Op_greaterequal',
['=='] = 'Op_equal',
['!='] = 'Op_notequal',
['!'] = 'Op_not',
['='] = 'Op_assign',
['&&'] = 'Op_and',
['||'] = 'Op_or',
['('] = 'LeftParen',
[')'] = 'RightParen',
['{'] = 'LeftBrace',
['}'] = 'RightBrace',
[';'] = 'Semicolon',
[','] = 'Comma',
['if'] = 'Keyword_if',
['else'] = 'Keyword_else',
['while'] = 'Keyword_while',
['print'] = 'Keyword_print',
['putc'] = 'Keyword_putc',
}
return token_name |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #HicEst | HicEst | DO i = 2, 100 ! 1 is HicEst.exe
EDIT(Text=$CMD_LINE, SePaRators='-"', ITeM=i, IF ' ', EXit, ENDIF, Parse=cmd, GetPosition=position)
IF(position > 0) WRITE(Messagebox) cmd
ENDDO |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Icon_and_Unicon | Icon and Unicon | procedure main(arglist)
every write(!arglist)
end |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Component_Pascal | Component Pascal |
(* Comments (* can nest *)
and they can span multiple lines.
*)
|
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Crystal | Crystal | # currently, Crystal only supports single-line comments
# This is a doc comment. Any line *directly* above (no blank lines) a module, class, or method is considered a doc comment
# Doc comments are used to generate documentation with `crystal docs`
class Foo
end |
http://rosettacode.org/wiki/Conway%27s_Game_of_Life | Conway's Game of Life | The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 when alive, or 0 when dead, in an m-by-m (or m×m) square array of cells.
We calculate N - the sum of live cells in C's eight-location neighbourhood, then cell C is alive or dead in the next generation based on the following table:
C N new C
1 0,1 -> 0 # Lonely
1 4,5,6,7,8 -> 0 # Overcrowded
1 2,3 -> 1 # Lives
0 3 -> 1 # It takes three to give birth!
0 0,1,2,4,5,6,7,8 -> 0 # Barren
Assume cells beyond the boundary are always dead.
The "game" is actually a zero-player game, meaning that its evolution is determined by its initial state, needing no input from human players. One interacts with the Game of Life by creating an initial configuration and observing how it evolves.
Task
Although you should test your implementation on more complex examples such as the glider in a larger universe, show the action of the blinker (three adjoining cells in a row all alive), over three generations, in a 3 by 3 grid.
References
Its creator John Conway, explains the game of life. Video from numberphile on youtube.
John Conway Inventing Game of Life - Numberphile video.
Related task
Langton's ant - another well known cellular automaton.
| #Haskell | Haskell | import Data.Array.Unboxed
type Grid = UArray (Int,Int) Bool
-- The grid is indexed by (y, x).
life :: Int -> Int -> Grid -> Grid
{- Returns the given Grid advanced by one generation. -}
life w h old =
listArray b (map f (range b))
where b@((y1,x1),(y2,x2)) = bounds old
f (y, x) = ( c && (n == 2 || n == 3) ) || ( not c && n == 3 )
where c = get x y
n = count [get (x + x') (y + y') |
x' <- [-1, 0, 1], y' <- [-1, 0, 1],
not (x' == 0 && y' == 0)]
get x y | x < x1 || x > x2 = False
| y < y1 || y > y2 = False
| otherwise = old ! (y, x)
count :: [Bool] -> Int
count = length . filter id |
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include if-then-else and switch.
Less common are arithmetic if, ternary operator and Hash-based conditionals.
Arithmetic if allows tight control over computed gotos, which optimizers have a hard time to figure out.
| #ColdFusion | ColdFusion | <cfif x eq 3>
do something
<cfelseif x eq 4>
do something else
<cfelse>
do something else
</cfif> |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #Oforth | Oforth | : lexEqual asSet size 1 <= ;
: lexCmp(l) l l right( l size 1- ) zipWith(#<) and ; |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #ooRexx | ooRexx | /* REXX ---------------------------------------------------------------
* 28.06.2014 Walter Pachl
*--------------------------------------------------------------------*/
Call test 'ABC',.list~of('AA','BB','CC')
Call test 'AAA',.list~of('AA','AA','AA')
Call test 'ACB',.list~of('AA','CC','BB')
Exit
test: Procedure
Use Arg name,list
all_equal=1
increasing=1
Do i=0 To list~items-2
i1=i+1
Select
When list[i1]==list[i] Then increasing=0
When list[i1]<<list[i] Then Do
all_equal=0
increasing=0
End
When list[i1]>>list[i] Then all_equal=0
End
End
Select
When all_equal Then
Say 'List' name': all elements are equal'
When increasing Then
Say 'List' name': elements are in increasing order'
Otherwise
Say 'List' name': neither equal nor in increasing order'
End
Return |
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #Fortran | Fortran | SUBROUTINE QUIBBLE(TEXT,OXFORDIAN) !Punctuates a list with commas and stuff.
CHARACTER*(*) TEXT !The text, delimited by spaces.
LOGICAL OXFORDIAN !Just so.
INTEGER IST(6),LST(6) !Start and stop positions.
INTEGER N,L,I !Counters.
INTEGER L1,L2 !Fingers for the scan.
INTEGER MSG !Output unit.
COMMON /IODEV/MSG !Share.
Chop the text into words.
N = 0 !No words found.
L = LEN(TEXT) !Multiple trailing spaces - no worries.
L2 = 0 !Syncopation: where the previous chomp ended.
10 L1 = L2 !Thus, where a fresh scan should follow.
11 L1 = L1 + 1 !Advance one.
IF (L1.GT.L) GO TO 20 !Finished yet?
IF (TEXT(L1:L1).LE." ") GO TO 11 !No. Skip leading spaces.
L2 = L1 !Righto, L1 is the first non-blank.
12 L2 = L2 + 1 !Scan through the non-blanks.
IF (L2.GT.L) GO TO 13 !Is it safe to look?
IF (TEXT(L2:L2).GT." ") GO TO 12 !Yes. Speed through non-blanks.
13 N = N + 1 !Righto, a word is found in TEXT(L1:L2 - 1)
IST(N) = L1 !So, recall its first character.
LST(N) = L2 - 1 !And its last.
IF (L2.LT.L) GO TO 10 !Perhaps more text follows.
Comma time...
20 WRITE (MSG,21) "{" !Start the output.
21 FORMAT (A,$) !The $, obviously, specifies that the line is not finished.
DO I = 1,N !Step through the texts, there possibly being none.
IF (I.GT.1) THEN !If there has been a predecessor, supply separators.
IF (I.LT.N) THEN !Up to the last two, it's easy.
WRITE (MSG,21) ", " !Always just a comma.
ELSE IF (OXFORDIAN) THEN !But after the penultimate item, what?
WRITE (MSG,21) ", and " !Supply the comma omitted above: a double-power separator.
ELSE !One fewer comma, with possible ambiguity arising.
WRITE (MSG,21) " and " !A single separator.
END IF !So much for the style.
END IF !Enough with the separation.
WRITE (MSG,21) TEXT(IST(I):LST(I)) !The text at last!
END DO !On to the next text.
WRITE (MSG,"('}')") !End the line, marking the end of the text.
END !That was fun.
PROGRAM ENCOMMA !Punctuate a list with commas.
CHARACTER*(666) TEXT !Holds the text. Easily long enough.
INTEGER KBD,MSG,INF !Now for some messing.
COMMON /IODEV/MSG,KBD !Pass the word.
KBD = 5 !Standard input.
MSG = 6 !Standard output.
INF = 10 !Suitable for a disc file.
OPEN (INF,FILE="List.txt",ACTION = "READ") !Attach one.
10 WRITE (MSG,11) "To insert commas into lists..." !Announce.
11 FORMAT (A) !Just the text.
12 READ (INF,11,END = 20) TEXT !Grab the text, with trailing spaces to fill out TEXT.
CALL QUIBBLE(TEXT,.FALSE.) !One way to quibble.
GO TO 12 !Try for another.
20 REWIND (INF) !Back to the start of the file.
WRITE (MSG,11) !Set off a bit.
WRITE (MSG,11) "Oxford style..." !Announce the proper style.
21 READ (INF,11,END = 30) TEXT !Grab the text.
CALL QUIBBLE(TEXT,.TRUE.) !The other way to quibble.
GO TO 21 !Have another try.
Closedown
30 END !All files are closed by exiting. |
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Lua | Lua | function GenerateCombinations(tList, nMaxElements, tOutput, nStartIndex, nChosen, tCurrentCombination)
if not nStartIndex then
nStartIndex = 1
end
if not nChosen then
nChosen = 0
end
if not tOutput then
tOutput = {}
end
if not tCurrentCombination then
tCurrentCombination = {}
end
if nChosen == nMaxElements then
-- Must copy the table to avoid all elements referring to a single reference
local tCombination = {}
for k,v in pairs(tCurrentCombination) do
tCombination[k] = v
end
table.insert(tOutput, tCombination)
return
end
local nIndex = 1
for k,v in pairs(tList) do
if nIndex >= nStartIndex then
tCurrentCombination[nChosen + 1] = tList[nIndex]
GenerateCombinations(tList, nMaxElements, tOutput, nIndex, nChosen + 1, tCurrentCombination)
end
nIndex = nIndex + 1
end
return tOutput
end
tDonuts = {"iced", "jam", "plain"}
tCombinations = GenerateCombinations(tDonuts, #tDonuts)
for nCombination,tCombination in ipairs(tCombinations) do
print("Combination " .. tostring(nCombination))
for nIndex,strFlavor in ipairs(tCombination) do
print("+" .. strFlavor)
end
end
|
http://rosettacode.org/wiki/Combinations_and_permutations | Combinations and permutations |
This page uses content from Wikipedia. The original article was at Combination. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
This page uses content from Wikipedia. The original article was at Permutation. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Implement the combination (nCk) and permutation (nPk) operators in the target language:
n
C
k
=
(
n
k
)
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle ^{n}\operatorname {C} _{k}={\binom {n}{k}}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
See the Wikipedia articles for a more detailed description.
To test, generate and print examples of:
A sample of permutations from 1 to 12 and Combinations from 10 to 60 using exact Integer arithmetic.
A sample of permutations from 5 to 15000 and Combinations from 100 to 1000 using approximate Floating point arithmetic.
This 'floating point' code could be implemented using an approximation, e.g., by calling the Gamma function.
Related task
Evaluate binomial coefficients
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Scheme | Scheme |
(define (combinations n k)
(do ((i 0 (+ 1 i))
(res 1 (/ (* res (- n i))
(- k i))))
((= i k) res)))
(define (permutations n k)
(do ((i 0 (+ 1 i))
(res 1 (* res (- n i))))
((= i k) res)))
(display "P(4,2) = ") (display (permutations 4 2)) (newline)
(display "P(8,2) = ") (display (permutations 8 2)) (newline)
(display "P(10,8) = ") (display (permutations 10 8)) (newline)
(display "C(10,8) = ") (display (combinations 10 8)) (newline)
(display "C(20,8) = ") (display (combinations 20 8)) (newline)
(display "C(60,58) = ") (display (combinations 60 58)) (newline)
(display "P(1000,10) = ") (display (permutations 1000 10)) (newline)
(display "P(1000,20) = ") (display (permutations 1000 20)) (newline)
(display "P(15000,2) = ") (display (permutations 15000 3)) (newline)
(display "C(1000,10) = ") (display (combinations 1000 10)) (newline)
(display "C(1000,999) = ") (display (combinations 1000 999)) (newline)
(display "C(1000,1000) = ") (display (combinations 1000 1000)) (newline)
(display "C(15000,14998) = ") (display (combinations 15000 14998)) (newline)
|
http://rosettacode.org/wiki/Compiler/lexical_analyzer | Compiler/lexical analyzer | Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer, or scanner (though "scanner" is also used to refer to the first stage of a lexer).
Task[edit]
Create a lexical analyzer for the simple programming language specified below. The
program should read input from a file and/or stdin, and write output to a file and/or
stdout. If the language being used has a lexer module/library/class, it would be great
if two versions of the solution are provided: One without the lexer module, and one with.
Input Specification
The simple programming language to be analyzed is more or less a subset of C. It supports the following tokens:
Operators
Name
Common name
Character sequence
Op_multiply
multiply
*
Op_divide
divide
/
Op_mod
mod
%
Op_add
plus
+
Op_subtract
minus
-
Op_negate
unary minus
-
Op_less
less than
<
Op_lessequal
less than or equal
<=
Op_greater
greater than
>
Op_greaterequal
greater than or equal
>=
Op_equal
equal
==
Op_notequal
not equal
!=
Op_not
unary not
!
Op_assign
assignment
=
Op_and
logical and
&&
Op_or
logical or
¦¦
The - token should always be interpreted as Op_subtract by the lexer. Turning some Op_subtract into Op_negate will be the job of the syntax analyzer, which is not part of this task.
Symbols
Name
Common name
Character
LeftParen
left parenthesis
(
RightParen
right parenthesis
)
LeftBrace
left brace
{
RightBrace
right brace
}
Semicolon
semi-colon
;
Comma
comma
,
Keywords
Name
Character sequence
Keyword_if
if
Keyword_else
else
Keyword_while
while
Keyword_print
print
Keyword_putc
putc
Identifiers and literals
These differ from the the previous tokens, in that each occurrence of them has a value associated with it.
Name
Common name
Format description
Format regex
Value
Identifier
identifier
one or more letter/number/underscore characters, but not starting with a number
[_a-zA-Z][_a-zA-Z0-9]*
as is
Integer
integer literal
one or more digits
[0-9]+
as is, interpreted as a number
Integer
char literal
exactly one character (anything except newline or single quote) or one of the allowed escape sequences, enclosed by single quotes
'([^'\n]|\\n|\\\\)'
the ASCII code point number of the character, e.g. 65 for 'A' and 10 for '\n'
String
string literal
zero or more characters (anything except newline or double quote), enclosed by double quotes
"[^"\n]*"
the characters without the double quotes and with escape sequences converted
For char and string literals, the \n escape sequence is supported to represent a new-line character.
For char and string literals, to represent a backslash, use \\.
No other special sequences are supported. This means that:
Char literals cannot represent a single quote character (value 39).
String literals cannot represent strings containing double quote characters.
Zero-width tokens
Name
Location
End_of_input
when the end of the input stream is reached
White space
Zero or more whitespace characters, or comments enclosed in /* ... */, are allowed between any two tokens, with the exceptions noted below.
"Longest token matching" is used to resolve conflicts (e.g., in order to match <= as a single token rather than the two tokens < and =).
Whitespace is required between two tokens that have an alphanumeric character or underscore at the edge.
This means: keywords, identifiers, and integer literals.
e.g. ifprint is recognized as an identifier, instead of the keywords if and print.
e.g. 42fred is invalid, and neither recognized as a number nor an identifier.
Whitespace is not allowed inside of tokens (except for chars and strings where they are part of the value).
e.g. & & is invalid, and not interpreted as the && operator.
For example, the following two program fragments are equivalent, and should produce the same token stream except for the line and column positions:
if ( p /* meaning n is prime */ ) {
print ( n , " " ) ;
count = count + 1 ; /* number of primes found so far */
}
if(p){print(n," ");count=count+1;}
Complete list of token names
End_of_input Op_multiply Op_divide Op_mod Op_add Op_subtract
Op_negate Op_not Op_less Op_lessequal Op_greater Op_greaterequal
Op_equal Op_notequal Op_assign Op_and Op_or Keyword_if
Keyword_else Keyword_while Keyword_print Keyword_putc LeftParen RightParen
LeftBrace RightBrace Semicolon Comma Identifier Integer
String
Output Format
The program output should be a sequence of lines, each consisting of the following whitespace-separated fields:
the line number where the token starts
the column number where the token starts
the token name
the token value (only for Identifier, Integer, and String tokens)
the number of spaces between fields is up to you. Neatly aligned is nice, but not a requirement.
This task is intended to be used as part of a pipeline, with the other compiler tasks - for example:
lex < hello.t | parse | gen | vm
Or possibly:
lex hello.t lex.out
parse lex.out parse.out
gen parse.out gen.out
vm gen.out
This implies that the output of this task (the lexical analyzer) should be suitable as input to any of the Syntax Analyzer task programs.
Diagnostics
The following error conditions should be caught:
Error
Example
Empty character constant
''
Unknown escape sequence.
\r
Multi-character constant.
'xx'
End-of-file in comment. Closing comment characters not found.
End-of-file while scanning string literal. Closing string character not found.
End-of-line while scanning string literal. Closing string character not found before end-of-line.
Unrecognized character.
|
Invalid number. Starts like a number, but ends in non-numeric characters.
123abc
Test Cases
Input
Output
Test Case 1:
/*
Hello world
*/
print("Hello, World!\n");
4 1 Keyword_print
4 6 LeftParen
4 7 String "Hello, World!\n"
4 24 RightParen
4 25 Semicolon
5 1 End_of_input
Test Case 2:
/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");
4 1 Identifier phoenix_number
4 16 Op_assign
4 18 Integer 142857
4 24 Semicolon
5 1 Keyword_print
5 6 LeftParen
5 7 Identifier phoenix_number
5 21 Comma
5 23 String "\n"
5 27 RightParen
5 28 Semicolon
6 1 End_of_input
Test Case 3:
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
5 16 Keyword_print
5 40 Op_subtract
6 16 Keyword_putc
6 40 Op_less
7 16 Keyword_if
7 40 Op_greater
8 16 Keyword_else
8 40 Op_lessequal
9 16 Keyword_while
9 40 Op_greaterequal
10 16 LeftBrace
10 40 Op_equal
11 16 RightBrace
11 40 Op_notequal
12 16 LeftParen
12 40 Op_and
13 16 RightParen
13 40 Op_or
14 16 Op_subtract
14 40 Semicolon
15 16 Op_not
15 40 Comma
16 16 Op_multiply
16 40 Op_assign
17 16 Op_divide
17 40 Integer 42
18 16 Op_mod
18 40 String "String literal"
19 16 Op_add
19 40 Identifier variable_name
20 26 Integer 10
21 26 Integer 92
22 26 Integer 32
23 1 End_of_input
Test Case 4:
/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");
2 1 Keyword_print
2 6 LeftParen
2 7 Integer 42
2 9 RightParen
2 10 Semicolon
3 1 Keyword_print
3 6 LeftParen
3 7 String "\nHello World\nGood Bye\nok\n"
3 38 RightParen
3 39 Semicolon
4 1 Keyword_print
4 6 LeftParen
4 7 String "Print a slash n - \\n.\n"
4 33 RightParen
4 34 Semicolon
5 1 End_of_input
Additional examples
Your solution should pass all the test cases above and the additional tests found Here.
Reference
The C and Python versions can be considered reference implementations.
Related Tasks
Syntax Analyzer task
Code Generator task
Virtual Machine Interpreter task
AST Interpreter task
| #M2000_Interpreter | M2000 Interpreter |
Module lexical_analyzer {
a$={/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
}
lim=Len(a$)
LineNo=1
ColumnNo=1
Document Output$
Buffer Scanner as Integer*lim
Return Scanner, 0:=a$
offset=0
buffer1$=""
flag_rem=true
Ahead=lambda Scanner (a$, offset)->{
=false
Try {
\\ second parameter is the offset in buffer units
\\ third parameter is length in bytes
=Eval$(Scanner, offset,2*len(a$))=a$
}
}
Ahead2=lambda Scanner (a$, offset)->{
=false
Try {
=Eval$(Scanner, offset,2) ~ a$
}
}
const nl$=chr$(13)+chr$(10), quo$="""", er$="@", Ansi=3
Try {
Do
If Ahead("/*", offset) Then {
offset+=2 : ColumnNo+=2
While not Ahead("*/", offset)
If Ahead(nl$, offset) Then
lineNo++: ColumnNo=1 : offset+=2
Else
offset++ : ColumnNo++
End If
if offset>lim then
Error "End-of-file in comment. Closing comment characters not found"+er$
End if
End While
offset+=2 : ColumnNo+=2
} Else.if Ahead(nl$, offset) Then{
LineNo++: ColumnNo=1
offset+=2
} Else.if Ahead(quo$, offset) Then {
Output$=format$("{0::-10}{1::-10} ", LineNo, ColumnNo)
offset++ : ColumnNo++
strin=offset
While not Ahead(quo$, offset)
If Ahead("/", offset) Then
offset+=2 : ColumnNo+=2
else
offset++ : ColumnNo++
End if
checkerror()
End While
Output$="String "+quote$(Eval$(Scanner, strin, (offset-strin)*2))+nl$
offset++ : ColumnNo++
} Else.if Ahead("'", offset) Then {
Output$=format$("{0::-10}{1::-10} ", LineNo, ColumnNo)
offset++ : ColumnNo++
strin=offset
While not Ahead("'", offset)
If Ahead("/", offset) Then
offset+=2 : ColumnNo+=2
else
offset++ : ColumnNo++
End if
checkerror()
End While
lit$=format$(Eval$(Scanner, strin, (offset-strin)*2))
select case len(lit$)
case 1
Output$="Integer "+str$(asc(lit$),0)+nl$
case >1
{Error "Multi-character constant."+er$}
case 0
{Error "Empty character constant."+er$}
end select
offset++ : ColumnNo++
} Else.if Ahead2("[a-z]", offset) Then {
strin=offset
Output$=format$("{0::-10}{1::-10} ", LineNo, ColumnNo)
offset++ : ColumnNo++
While Ahead2("[a-zA-Z0-9_]", offset)
offset++ : ColumnNo++
End While
Keywords(Eval$(Scanner, strin, (offset-strin)*2))
} Else.if Ahead2("[0-9]", offset) Then {
strin=offset
Output$=format$("{0::-10}{1::-10} Integer ", LineNo, ColumnNo)
offset++ : ColumnNo++
While Ahead2("[0-9]", offset)
offset++ : ColumnNo++
End While
if Ahead2("[a-zA-Z_]", offset) then
{Error " Invalid number. Starts like a number, but ends in non-numeric characters."+er$}
else
Output$=Eval$(Scanner, strin, (offset-strin)*2)+nl$
end if
} Else {
Symbols(Eval$(Scanner, Offset, 2))
offset++ : ColumnNo++
}
Until offset>=lim
}
er1$=leftpart$(error$,er$)
if er1$<>"" then
Print
Report "Error:"+er1$
Output$="(Error)"+nl$+"Error:"+er1$
else
Output$=format$("{0::-10}{1::-10}", LineNo, ColumnNo)+" End_of_Input"+nl$
end if
Clipboard Output$
Save.Doc Output$, "lex.t", Ansi
document lex$
Load.Doc lex$,"lex.t", Ansi
Report lex$
Sub Keywords(a$)
select case a$
case "if"
a$="Keyword_if"
case "else"
a$="Keyword_else"
case "while"
a$="Keyword_while"
case "print"
a$="Keyword_print"
case "putc"
a$="Keyword_putc"
else case
a$="Identifier "+a$
end select
Output$=a$+nl$
End sub
Sub Symbols(a$)
select case a$
case " ", chr$(9)
a$=""
case "("
a$="LeftParen"
case ")"
a$="RightParen"
case "{"
a$="LeftBrace"
case "}"
a$="RightBrace"
case ";"
a$="Semicolon"
case ","
a$="Comma"
case "*"
a$="Op_multiply"
case "/"
a$="Op_divide"
case "+"
a$="Op_add"
case "-"
a$="Op_subtract"
case "%"
a$="Op_mod"
case "<"
{ if Ahead("=", offset+1) Then
offset++
a$="Op_lessequal"
ColumnNo++
else
a$="Op_less"
end if
}
case ">"
{ if Ahead("=", offset+1) Then
offset++
ColumnNo++
a$="Op_greaterequal"
else
a$="Op_greater"
end if
}
case "="
{ if Ahead("=", offset+1) Then
offset++
ColumnNo++
a$="Op_equal"
else
a$="Op_assign"
end if
}
case "!"
{ if Ahead("=", offset+1) Then
offset++
ColumnNo++
a$="Op_notequal"
else
a$="Op_not"
end if
}
case "&"
{ if Ahead("&", offset+1) Then
offset++
ColumnNo++
a$="Op_and"
else
a$=""
end if
}
case "|"
{ if Ahead("|", offset+1) Then
offset++
ColumnNo++
a$="Op_or"
else
a$=""
end if
}
else case
{Error "Unrecognized character."+er$}
end select
if a$<>"" then
Output$=format$("{0::-10}{1::-10} ", LineNo, ColumnNo)+a$+nl$
end if
End Sub
Sub checkerror()
if offset>lim then {
Error "End-of-line while scanning string literal. Closing string character not found before end-of-line."+er$
} else.if Ahead(nl$,offset) then {
Error "End-of-file while scanning string literal. Closing string character not found."+er$
}
End Sub
}
lexical_analyzer
|
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Io | Io | System args foreach(a, a println) |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Ioke | Ioke | System programArguments each(println) |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #J | J | ARGV |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #D | D | void main() {
// A single line comment.
/* This is a simple C-style comment that can't be nested.
Comments mostly work similar to C, newlines are irrelevant.
*/
/+ This is a nestable comment
/+ See?
+/
+/
/// Documentation single line comment.
/**
Simple C-style documentation comment.
*/
/++
Nestable documenttion comment.
+/
} |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Dart | Dart | // This is a single line comment, which lasts until the end of the line. The Dart linter prefers this one.
/* This is also a valid single line comment. Unlike the first one, this one terminates after one of these -> */
/*
You can use the syntax above to make multi line comments as well.
Like this!
*/
/// These are doc comments. You can use dartdoc to generate doc pages for your classes with these.
///
/// Formatting [variable] and [function] names like so allows dartdoc to link to the documentation for those entities.
|
http://rosettacode.org/wiki/Conway%27s_Game_of_Life | Conway's Game of Life | The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 when alive, or 0 when dead, in an m-by-m (or m×m) square array of cells.
We calculate N - the sum of live cells in C's eight-location neighbourhood, then cell C is alive or dead in the next generation based on the following table:
C N new C
1 0,1 -> 0 # Lonely
1 4,5,6,7,8 -> 0 # Overcrowded
1 2,3 -> 1 # Lives
0 3 -> 1 # It takes three to give birth!
0 0,1,2,4,5,6,7,8 -> 0 # Barren
Assume cells beyond the boundary are always dead.
The "game" is actually a zero-player game, meaning that its evolution is determined by its initial state, needing no input from human players. One interacts with the Game of Life by creating an initial configuration and observing how it evolves.
Task
Although you should test your implementation on more complex examples such as the glider in a larger universe, show the action of the blinker (three adjoining cells in a row all alive), over three generations, in a 3 by 3 grid.
References
Its creator John Conway, explains the game of life. Video from numberphile on youtube.
John Conway Inventing Game of Life - Numberphile video.
Related task
Langton's ant - another well known cellular automaton.
| #HolyC | HolyC | global limit
procedure main(args)
n := args[1] | 50 # default is a 50x50 grid
limit := args[2] | &null # optional limit to number of generations
write("Enter the starting pattern, end with EOF")
grid := getInitialGrid(n)
play(grid)
end
# This procedure reads in the initial pattern, inserting it
# into an nXn grid of cells. The nXn grid also gets a
# new border of empty cells, which just makes the test simpler
# for determining what do with a cell on each generation.
# It would be better to let the user move the cursor and click
# on cells to create/delete living cells, but this version
# assumes a simple ASCII terminal.
procedure getInitialGrid(n)
static notBlank, allStars
initial {
notBlank := ~' '
allStars := repl("*",*notBlank)
}
g := [] # store as an array of strings
put(g,repl(" ",n))
while r := read() do { # read in rows of grid
r := left(r,n) # force each to length n
put(g," "||map(r,notBlank,allStars)||" ") # and making any life a '*'
}
while *g ~= (n+2) do
put(g,repl(" ",n))
return g
end
# Simple-minded procedure to 'play' Life from a starting grid.
procedure play(grid)
while not allDone(grid) do {
display(grid)
grid := onePlay(grid)
}
end
# Display the grid
procedure display(g)
write(repl("-",*g[1]))
every write(!g)
write(repl("-",*g[1]))
end
# Compute one generation of Life from the current one.
procedure onePlay(g)
ng := []
every put(ng, !g) # new generation starts as copy of old
every ng[r := 2 to *g-1][c := 2 to *g-1] := case sum(g,r,c) of {
3: "*" # cell lives (or is born)
2: g[r][c] # cell unchanged
default: " " # cell dead
}
return ng
end
# Return the number of living cells surrounding the current cell.
procedure sum(g,r,c)
cnt := 0
every (i := -1 to 1, j := -1 to 1) do
if ((i ~= 0) | (j ~= 0)) & (g[r+i][c+j] == "*") then cnt +:= 1
return cnt
end
# Check to see if all the cells have died or we've exceeded the
# number of allowed generations.
procedure allDone(g)
static count
initial count := 0
return ((count +:= 1) > \limit) | (trim(!g) == " ")
end |
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include if-then-else and switch.
Less common are arithmetic if, ternary operator and Hash-based conditionals.
Arithmetic if allows tight control over computed gotos, which optimizers have a hard time to figure out.
| #Comal | Comal | IF condition THEN PRINT "True" |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #PARI.2FGP | PARI/GP | allEqual(strings)=#Set(strings)<2
inOrder(strings)=Set(strings)==strings |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #Perl | Perl | use List::Util 1.33 qw(all);
all { $strings[0] eq $strings[$_] } 1..$#strings # All equal
all { $strings[$_-1] lt $strings[$_] } 1..$#strings # Strictly ascending |
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #FreeBASIC | FreeBASIC |
' FB 1.05.0 Win64
Sub Split(s As String, sep As String, result() As String)
Dim As Integer i, j, count = 0
Dim temp As String
Dim As Integer position(Len(s) + 1)
position(0) = 0
For i = 0 To Len(s) - 1
For j = 0 To Len(sep) - 1
If s[i] = sep[j] Then
count += 1
position(count) = i + 1
End If
Next j
Next i
position(count + 1) = Len(s) + 1
Redim result(count)
For i = 1 To count + 1
result(i - 1) = Mid(s, position(i - 1) + 1, position(i) - position(i - 1) - 1)
Next
End Sub
Function CommaQuibble(s As String) As String
Dim i As Integer
Dim As String result
Dim As String words()
s = Trim(s, Any "[]""")
' Now remove internal quotes
Split s, """", words()
s = ""
For i = 0 To UBound(words)
s &= words(i)
Next
' Now split 's' using the comma as separator
Erase words
Split s, ",", words()
' And re-assemble the string in the desired format
result = "{"
For i = 0 To UBound(words)
If i = 0 Then
result &= words(i)
ElseIf i = UBound(words) Then
result &= " and " & words(i)
Else
result &= ", " + words(i)
EndIf
Next
Return result & "}"
End Function
' As 3 of the strings contain embedded quotes these need to be doubled in FB
Print CommaQuibble("[]")
Print CommaQuibble("[""ABC""]")
Print CommaQuibble("[""ABC"",""DEF""]")
Print CommaQuibble("[""ABC"",""DEF"",""G"",""H""]")
Print
Print "Press any key to quit the program"
Sleep
|
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Maple | Maple | with(combinat):
chooserep:=(s,k)->choose([seq(op(s),i=1..k)],k):
chooserep({iced,jam,plain},2);
# [[iced, iced], [iced, jam], [iced, plain], [jam, jam], [jam, plain], [plain, plain]]
numbchooserep:=(s,k)->binomial(nops(s)+k-1,k);
numbchooserep({iced,jam,plain},2);
# 6 |
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Mathematica_.2F_Wolfram_Language | Mathematica / Wolfram Language | DeleteDuplicates[Tuples[{"iced", "jam", "plain"}, 2],Sort[#1] == Sort[#2] &]
->{{"iced", "iced"}, {"iced", "jam"}, {"iced", "plain"}, {"jam", "jam"}, {"jam", "plain"}, {"plain", "plain"}}
Combi[x_, y_] := Binomial[(x + y) - 1, y]
Combi[3, 2]
-> 6
Combi[10, 3]
->220
|
http://rosettacode.org/wiki/Combinations_and_permutations | Combinations and permutations |
This page uses content from Wikipedia. The original article was at Combination. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
This page uses content from Wikipedia. The original article was at Permutation. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Implement the combination (nCk) and permutation (nPk) operators in the target language:
n
C
k
=
(
n
k
)
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle ^{n}\operatorname {C} _{k}={\binom {n}{k}}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
See the Wikipedia articles for a more detailed description.
To test, generate and print examples of:
A sample of permutations from 1 to 12 and Combinations from 10 to 60 using exact Integer arithmetic.
A sample of permutations from 5 to 15000 and Combinations from 100 to 1000 using approximate Floating point arithmetic.
This 'floating point' code could be implemented using an approximation, e.g., by calling the Gamma function.
Related task
Evaluate binomial coefficients
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Sidef | Sidef | func P(n, k) { n! / ((n-k)!) }
func C(n, k) { binomial(n, k) }
class Logarithm(value) {
method to_s {
var e = int(value/10.log)
"%.8fE%+d" % (exp(value - e*10.log), e)
}
}
func lstirling(n) {
n < 10 ? (lstirling(n+1) - log(n+1))
: (0.5*log(2*Num.pi*n) + n*log(n/Num.e + 1/(12*Num.e*n)))
}
func P_approx(n, k) {
Logarithm((lstirling(n) - lstirling(n -k)))
}
func C_approx(n, k) {
Logarithm((lstirling(n) - lstirling(n -k) - lstirling(k)))
}
say "=> Exact results:"
for n (1..12) {
var p = n//3
say "P(#{n}, #{p}) = #{P(n, p)}"
}
for n (10..60 `by` 10) {
var p = n//3
say "C(#{n}, #{p}) = #{C(n, p)}"
}
say '';
say "=> Floating point approximations:"
for n ([5, 50, 500, 1000, 5000, 15000]) {
var p = n//3
say "P(#{n}, #{p}) = #{P_approx(n, p)}"
}
for n (100..1000 `by` 100) {
var p = n//3
say "C(#{n}, #{p}) = #{C_approx(n, p)}"
} |
http://rosettacode.org/wiki/Compiler/lexical_analyzer | Compiler/lexical analyzer | Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer, or scanner (though "scanner" is also used to refer to the first stage of a lexer).
Task[edit]
Create a lexical analyzer for the simple programming language specified below. The
program should read input from a file and/or stdin, and write output to a file and/or
stdout. If the language being used has a lexer module/library/class, it would be great
if two versions of the solution are provided: One without the lexer module, and one with.
Input Specification
The simple programming language to be analyzed is more or less a subset of C. It supports the following tokens:
Operators
Name
Common name
Character sequence
Op_multiply
multiply
*
Op_divide
divide
/
Op_mod
mod
%
Op_add
plus
+
Op_subtract
minus
-
Op_negate
unary minus
-
Op_less
less than
<
Op_lessequal
less than or equal
<=
Op_greater
greater than
>
Op_greaterequal
greater than or equal
>=
Op_equal
equal
==
Op_notequal
not equal
!=
Op_not
unary not
!
Op_assign
assignment
=
Op_and
logical and
&&
Op_or
logical or
¦¦
The - token should always be interpreted as Op_subtract by the lexer. Turning some Op_subtract into Op_negate will be the job of the syntax analyzer, which is not part of this task.
Symbols
Name
Common name
Character
LeftParen
left parenthesis
(
RightParen
right parenthesis
)
LeftBrace
left brace
{
RightBrace
right brace
}
Semicolon
semi-colon
;
Comma
comma
,
Keywords
Name
Character sequence
Keyword_if
if
Keyword_else
else
Keyword_while
while
Keyword_print
print
Keyword_putc
putc
Identifiers and literals
These differ from the the previous tokens, in that each occurrence of them has a value associated with it.
Name
Common name
Format description
Format regex
Value
Identifier
identifier
one or more letter/number/underscore characters, but not starting with a number
[_a-zA-Z][_a-zA-Z0-9]*
as is
Integer
integer literal
one or more digits
[0-9]+
as is, interpreted as a number
Integer
char literal
exactly one character (anything except newline or single quote) or one of the allowed escape sequences, enclosed by single quotes
'([^'\n]|\\n|\\\\)'
the ASCII code point number of the character, e.g. 65 for 'A' and 10 for '\n'
String
string literal
zero or more characters (anything except newline or double quote), enclosed by double quotes
"[^"\n]*"
the characters without the double quotes and with escape sequences converted
For char and string literals, the \n escape sequence is supported to represent a new-line character.
For char and string literals, to represent a backslash, use \\.
No other special sequences are supported. This means that:
Char literals cannot represent a single quote character (value 39).
String literals cannot represent strings containing double quote characters.
Zero-width tokens
Name
Location
End_of_input
when the end of the input stream is reached
White space
Zero or more whitespace characters, or comments enclosed in /* ... */, are allowed between any two tokens, with the exceptions noted below.
"Longest token matching" is used to resolve conflicts (e.g., in order to match <= as a single token rather than the two tokens < and =).
Whitespace is required between two tokens that have an alphanumeric character or underscore at the edge.
This means: keywords, identifiers, and integer literals.
e.g. ifprint is recognized as an identifier, instead of the keywords if and print.
e.g. 42fred is invalid, and neither recognized as a number nor an identifier.
Whitespace is not allowed inside of tokens (except for chars and strings where they are part of the value).
e.g. & & is invalid, and not interpreted as the && operator.
For example, the following two program fragments are equivalent, and should produce the same token stream except for the line and column positions:
if ( p /* meaning n is prime */ ) {
print ( n , " " ) ;
count = count + 1 ; /* number of primes found so far */
}
if(p){print(n," ");count=count+1;}
Complete list of token names
End_of_input Op_multiply Op_divide Op_mod Op_add Op_subtract
Op_negate Op_not Op_less Op_lessequal Op_greater Op_greaterequal
Op_equal Op_notequal Op_assign Op_and Op_or Keyword_if
Keyword_else Keyword_while Keyword_print Keyword_putc LeftParen RightParen
LeftBrace RightBrace Semicolon Comma Identifier Integer
String
Output Format
The program output should be a sequence of lines, each consisting of the following whitespace-separated fields:
the line number where the token starts
the column number where the token starts
the token name
the token value (only for Identifier, Integer, and String tokens)
the number of spaces between fields is up to you. Neatly aligned is nice, but not a requirement.
This task is intended to be used as part of a pipeline, with the other compiler tasks - for example:
lex < hello.t | parse | gen | vm
Or possibly:
lex hello.t lex.out
parse lex.out parse.out
gen parse.out gen.out
vm gen.out
This implies that the output of this task (the lexical analyzer) should be suitable as input to any of the Syntax Analyzer task programs.
Diagnostics
The following error conditions should be caught:
Error
Example
Empty character constant
''
Unknown escape sequence.
\r
Multi-character constant.
'xx'
End-of-file in comment. Closing comment characters not found.
End-of-file while scanning string literal. Closing string character not found.
End-of-line while scanning string literal. Closing string character not found before end-of-line.
Unrecognized character.
|
Invalid number. Starts like a number, but ends in non-numeric characters.
123abc
Test Cases
Input
Output
Test Case 1:
/*
Hello world
*/
print("Hello, World!\n");
4 1 Keyword_print
4 6 LeftParen
4 7 String "Hello, World!\n"
4 24 RightParen
4 25 Semicolon
5 1 End_of_input
Test Case 2:
/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");
4 1 Identifier phoenix_number
4 16 Op_assign
4 18 Integer 142857
4 24 Semicolon
5 1 Keyword_print
5 6 LeftParen
5 7 Identifier phoenix_number
5 21 Comma
5 23 String "\n"
5 27 RightParen
5 28 Semicolon
6 1 End_of_input
Test Case 3:
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
5 16 Keyword_print
5 40 Op_subtract
6 16 Keyword_putc
6 40 Op_less
7 16 Keyword_if
7 40 Op_greater
8 16 Keyword_else
8 40 Op_lessequal
9 16 Keyword_while
9 40 Op_greaterequal
10 16 LeftBrace
10 40 Op_equal
11 16 RightBrace
11 40 Op_notequal
12 16 LeftParen
12 40 Op_and
13 16 RightParen
13 40 Op_or
14 16 Op_subtract
14 40 Semicolon
15 16 Op_not
15 40 Comma
16 16 Op_multiply
16 40 Op_assign
17 16 Op_divide
17 40 Integer 42
18 16 Op_mod
18 40 String "String literal"
19 16 Op_add
19 40 Identifier variable_name
20 26 Integer 10
21 26 Integer 92
22 26 Integer 32
23 1 End_of_input
Test Case 4:
/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");
2 1 Keyword_print
2 6 LeftParen
2 7 Integer 42
2 9 RightParen
2 10 Semicolon
3 1 Keyword_print
3 6 LeftParen
3 7 String "\nHello World\nGood Bye\nok\n"
3 38 RightParen
3 39 Semicolon
4 1 Keyword_print
4 6 LeftParen
4 7 String "Print a slash n - \\n.\n"
4 33 RightParen
4 34 Semicolon
5 1 End_of_input
Additional examples
Your solution should pass all the test cases above and the additional tests found Here.
Reference
The C and Python versions can be considered reference implementations.
Related Tasks
Syntax Analyzer task
Code Generator task
Virtual Machine Interpreter task
AST Interpreter task
| #Mercury | Mercury | % -*- mercury -*-
%
% Compile with maybe something like:
% mmc -O4 --intermod-opt -E --make --warn-non-tail-recursion self-and-mutual lex
%
:- module lex.
:- interface.
:- import_module io.
:- pred main(io::di, io::uo) is det.
:- implementation.
:- import_module char.
:- import_module exception.
:- import_module int.
:- import_module list.
:- import_module stack.
:- import_module string.
:- type token_t
---> token_ELSE
; token_IF
; token_PRINT
; token_PUTC
; token_WHILE
; token_MULTIPLY
; token_DIVIDE
; token_MOD
; token_ADD
; token_SUBTRACT
; token_NEGATE
; token_LESS
; token_LESSEQUAL
; token_GREATER
; token_GREATEREQUAL
; token_EQUAL
; token_NOTEQUAL
; token_NOT
; token_ASSIGN
; token_AND
; token_OR
; token_LEFTPAREN
; token_RIGHTPAREN
; token_LEFTBRACE
; token_RIGHTBRACE
; token_SEMICOLON
; token_COMMA
; token_IDENTIFIER
; token_INTEGER
; token_STRING
; token_END_OF_INPUT.
:- type ch_t % The type of a fetched character.
---> {int, % A character or `eof', stored as an int.
int, % The line number.
int}. % The column number.
:- type inp_t % The `inputter' type. Fetches one character.
---> inp_t(inpf :: text_input_stream,
line_no :: int,
column_no :: int,
pushback :: stack(ch_t)).
:- type toktup_t % The type of a scanned token with its argument.
---> {token_t, % The token kind.
string, % An argument. (May or may not be meaningful.)
int, % The starting line number.
int}. % The starting column number.
main(!IO) :-
command_line_arguments(Args, !IO),
(
if (Args = [])
then (InpF_filename = "-",
OutF_filename = "-",
main_program(InpF_filename, OutF_filename, !IO))
else if (Args = [F1])
then (InpF_filename = F1,
OutF_filename = "-",
main_program(InpF_filename, OutF_filename, !IO))
else if (Args = [F1, F2])
then (InpF_filename = F1,
OutF_filename = F2,
main_program(InpF_filename, OutF_filename, !IO))
else usage_error(!IO)
).
:- pred main_program(string::in, string::in, io::di, io::uo) is det.
main_program(InpF_filename, OutF_filename, !IO) :-
open_InpF(InpF, InpF_filename, !IO),
open_OutF(OutF, OutF_filename, !IO),
init(InpF, Inp0),
scan_text(OutF, Inp0, _, !IO).
:- pred open_InpF(text_input_stream::out, string::in,
io::di, io::uo) is det.
open_InpF(InpF, InpF_filename, !IO) :-
if (InpF_filename = "-")
then (InpF = io.stdin_stream)
else
(
open_input(InpF_filename, InpF_result, !IO),
(
if (InpF_result = ok(F))
then (InpF = F)
else throw("Error: cannot open " ++ InpF_filename ++
" for input")
)
).
:- pred open_OutF(text_output_stream::out, string::in,
io::di, io::uo) is det.
open_OutF(OutF, OutF_filename, !IO) :-
if (OutF_filename = "-")
then (OutF = io.stdout_stream)
else
(
open_output(OutF_filename, OutF_result, !IO),
(
if (OutF_result = ok(F))
then (OutF = F)
else throw("Error: cannot open " ++ OutF_filename ++
" for output")
)
).
:- pred usage_error(io::di, io::uo) is det.
usage_error(!IO) :-
progname("lex", ProgName, !IO),
(io.format("Usage: %s [INPUT_FILE [OUTPUT_FILE]]\n",
[s(ProgName)], !IO)),
(io.write_string("If INPUT_FILE is \"-\" or not present then standard input is used.\n",
!IO)),
(io.write_string("If OUTPUT_FILE is \"-\" or not present then standard output is used.\n",
!IO)),
set_exit_status(1, !IO).
:- pred scan_text(text_output_stream::in, inp_t::in, inp_t::out,
io::di, io::uo) is det.
scan_text(OutF, !Inp, !IO) :-
get_next_token(TokTup, !Inp, !IO),
print_token(TokTup, OutF, !IO),
{Tok, _, _, _} = TokTup,
(
if (Tok = token_END_OF_INPUT)
then true
else scan_text(OutF, !Inp, !IO)
).
:- pred print_token(toktup_t::in, text_output_stream::in,
io::di, io::uo) is det.
print_token(TokTup, OutF, !IO) :-
{Tok, Arg, Line_no, Column_no} = TokTup,
token_name(Tok) = TokName,
(io.format(OutF, "%5d %5d %s",
[i(Line_no), i(Column_no), s(TokName)],
!IO)),
(
if (Tok = token_IDENTIFIER)
then (io.format(OutF, " %s", [s(Arg)], !IO))
else if (Tok = token_INTEGER)
then (io.format(OutF, " %s", [s(Arg)], !IO))
else if (Tok = token_STRING)
then (io.format(OutF, " %s", [s(Arg)], !IO))
else true
),
(io.format(OutF, "\n", [], !IO)).
:- func token_name(token_t) = string is det.
:- pred token_name(token_t::in, string::out) is det.
token_name(Tok) = Str :- token_name(Tok, Str).
token_name(token_ELSE, "Keyword_else").
token_name(token_IF, "Keyword_if").
token_name(token_PRINT, "Keyword_print").
token_name(token_PUTC, "Keyword_putc").
token_name(token_WHILE, "Keyword_while").
token_name(token_MULTIPLY, "Op_multiply").
token_name(token_DIVIDE, "Op_divide").
token_name(token_MOD, "Op_mod").
token_name(token_ADD, "Op_add").
token_name(token_SUBTRACT, "Op_subtract").
token_name(token_NEGATE, "Op_negate").
token_name(token_LESS, "Op_less").
token_name(token_LESSEQUAL, "Op_lessequal").
token_name(token_GREATER, "Op_greater").
token_name(token_GREATEREQUAL, "Op_greaterequal").
token_name(token_EQUAL, "Op_equal").
token_name(token_NOTEQUAL, "Op_notequal").
token_name(token_NOT, "Op_not").
token_name(token_ASSIGN, "Op_assign").
token_name(token_AND, "Op_and").
token_name(token_OR, "Op_or").
token_name(token_LEFTPAREN, "LeftParen").
token_name(token_RIGHTPAREN, "RightParen").
token_name(token_LEFTBRACE, "LeftBrace").
token_name(token_RIGHTBRACE, "RightBrace").
token_name(token_SEMICOLON, "Semicolon").
token_name(token_COMMA, "Comma").
token_name(token_IDENTIFIER, "Identifier").
token_name(token_INTEGER, "Integer").
token_name(token_STRING, "String").
token_name(token_END_OF_INPUT, "End_of_input").
:- pred get_next_token(toktup_t::out, inp_t::in, inp_t::out,
io::di, io::uo) is det.
get_next_token(TokTup, !Inp, !IO) :-
skip_spaces_and_comments(!Inp, !IO),
get_ch(Ch, !Inp, !IO),
{IChar, Line_no, Column_no} = Ch,
LN = Line_no,
CN = Column_no,
(
if (IChar = eof)
then
(
TokTup = {token_END_OF_INPUT, "", LN, CN}
)
else
(
Char = det_from_int(IChar),
(
if (Char = (','))
then (TokTup = {token_COMMA, ",", LN, CN})
else if (Char = (';'))
then (TokTup = {token_SEMICOLON, ";", LN, CN})
else if (Char = ('('))
then (TokTup = {token_LEFTPAREN, "(", LN, CN})
else if (Char = (')'))
then (TokTup = {token_RIGHTPAREN, ")", LN, CN})
else if (Char = ('{'))
then (TokTup = {token_LEFTBRACE, "{", LN, CN})
else if (Char = ('}'))
then (TokTup = {token_RIGHTBRACE, "}", LN, CN})
else if (Char = ('*'))
then (TokTup = {token_MULTIPLY, "*", LN, CN})
else if (Char = ('/'))
then (TokTup = {token_DIVIDE, "/", LN, CN})
else if (Char = ('%'))
then (TokTup = {token_MOD, "%", LN, CN})
else if (Char = ('+'))
then (TokTup = {token_ADD, "+", LN, CN})
else if (Char = ('-'))
then (TokTup = {token_SUBTRACT, "-", LN, CN})
else if (Char = ('<'))
then
(
get_ch(Ch1, !Inp, !IO),
Ch1 = {IChar1, _, _},
(
if (IChar1 = to_int('='))
then
(
TokTup = {token_LESSEQUAL, "<=", LN, CN}
)
else
(
push_back(Ch1, !Inp),
TokTup = {token_LESS, "<", LN, CN}
)
)
)
else if (Char = ('>'))
then
(
get_ch(Ch1, !Inp, !IO),
Ch1 = {IChar1, _, _},
(
if (IChar1 = to_int('='))
then
(
TokTup = {token_GREATEREQUAL, ">=", LN, CN}
)
else
(
push_back(Ch1, !Inp),
TokTup = {token_GREATER, ">", LN, CN}
)
)
)
else if (Char = ('='))
then
(
get_ch(Ch1, !Inp, !IO),
Ch1 = {IChar1, _, _},
(
if (IChar1 = to_int('='))
then
(
TokTup = {token_EQUAL, "==", LN, CN}
)
else
(
push_back(Ch1, !Inp),
TokTup = {token_ASSIGN, "=", LN, CN}
)
)
)
else if (Char = ('!'))
then
(
get_ch(Ch1, !Inp, !IO),
Ch1 = {IChar1, _, _},
(
if (IChar1 = to_int('='))
then
(
TokTup = {token_NOTEQUAL, "!=", LN, CN}
)
else
(
push_back(Ch1, !Inp),
TokTup = {token_NOT, "!", LN, CN}
)
)
)
else if (Char = ('&'))
then
(
get_ch(Ch1, !Inp, !IO),
Ch1 = {IChar1, _, _},
(
if (IChar1 = to_int('&'))
then
(
TokTup = {token_AND, "&&", LN, CN}
)
else throw("Error: unexpected character '" ++
from_char(Char) ++ "' at " ++
from_int(LN) ++ ":" ++
from_int(CN))
)
)
else if (Char = ('|'))
then
(
get_ch(Ch1, !Inp, !IO),
Ch1 = {IChar1, _, _},
(
if (IChar1 = to_int('|'))
then
(
TokTup = {token_OR, "||", LN, CN}
)
else throw("Error: unexpected character '" ++
from_char(Char) ++ "' at " ++
from_int(LN) ++ ":" ++
from_int(CN))
)
)
else if (Char = ('"'))
then
(
push_back(Ch, !Inp),
scan_string_literal(TokTup, !Inp, !IO)
)
else if (Char = ('\''))
then
(
push_back(Ch, !Inp),
scan_character_literal(TokTup, !Inp, !IO)
)
else if (is_alpha(Char))
then
(
push_back(Ch, !Inp),
scan_identifier_or_reserved_word(
TokTup, !Inp, !IO)
)
else if (is_digit(Char))
then
(
push_back(Ch, !Inp),
scan_integer_literal(TokTup, !Inp, !IO)
)
else
(
throw("Error: unexpected character '" ++
from_char(Char) ++ "' at " ++
from_int(LN) ++ ":" ++
from_int(CN))
)
)
)
).
:- pred skip_spaces_and_comments(inp_t::in, inp_t::out,
io::di, io::uo) is det.
skip_spaces_and_comments(!Inp, !IO) :-
get_ch(Ch, !Inp, !IO),
Ch = {IChar, _, _},
(
if (IChar = eof)
then push_back(Ch, !Inp)
else
if (is_whitespace(det_from_int(IChar)))
then skip_spaces_and_comments(!Inp, !IO)
else if (IChar = to_int('/'))
then
(
get_ch(Ch1, !Inp, !IO),
Ch1 = {IChar1, Line_no, Column_no},
(
if (IChar1 = to_int('*'))
then
(
scan_comment(Line_no, Column_no,
!Inp, !IO),
skip_spaces_and_comments(!Inp, !IO)
)
else
(
push_back(Ch1, !Inp),
push_back(Ch, !Inp)
)
)
)
else push_back(Ch, !Inp)
).
:- pred scan_comment(int::in, int::in, % line and column nos.
inp_t::in, inp_t::out,
io::di, io::uo) is det.
scan_comment(Line_no, Column_no, !Inp, !IO) :-
get_ch(Ch, !Inp, !IO),
{IChar, _, _} = Ch,
(
if (IChar = eof)
then throw("Error: unterminated comment " ++
"starting at " ++ from_int(Line_no) ++ ":" ++
from_int(Column_no))
else
(
det_from_int(IChar) = Char,
(
if (Char = ('*'))
then
(
get_ch(Ch1, !Inp, !IO),
{IChar1, _, _} = Ch1,
(
if (IChar1 = to_int('/'))
then true % End of comment has been reached.
else
(
push_back(Ch1, !Inp),
scan_comment(Line_no, Column_no, !Inp,
!IO)
)
)
)
else scan_comment(Line_no, Column_no, !Inp, !IO)
)
)
).
:- pred scan_character_literal(toktup_t::out,
inp_t::in, inp_t::out,
io::di, io::uo) is det.
scan_character_literal(TokTup, !Inp, !IO) :-
get_ch(Ch, !Inp, !IO),
Ch = {OpenQuote, Line_no, Column_no},
CloseQuote = OpenQuote,
scan_char_lit_contents(CodePoint, Line_no, Column_no,
!Inp, !IO),
check_char_lit_end(CloseQuote, Line_no, Column_no, !Inp, !IO),
Arg = from_int(CodePoint),
TokTup = {token_INTEGER, Arg, Line_no, Column_no}.
:- pred scan_char_lit_contents(int::out, int::in, int::in,
inp_t::in, inp_t::out,
io::di, io::uo) is det.
scan_char_lit_contents(CodePoint, Line_no, Column_no,
!Inp, !IO) :-
get_ch(Ch1, !Inp, !IO),
Ch1 = {IChar1, Line_no1, Column_no1},
(
if (IChar1 = eof)
then throw("Error: end of input in character literal " ++
"starting at " ++ from_int(Line_no) ++ ":" ++
from_int(Column_no))
else if (IChar1 = to_int('\\'))
then
(
get_ch(Ch2, !Inp, !IO),
Ch2 = {IChar2, _, _},
(if (IChar2 = eof)
then throw("Error: end of input in character literal " ++
"starting at " ++ from_int(Line_no) ++ ":" ++
from_int(Column_no))
else if (IChar2 = to_int('n'))
then (CodePoint = to_int('\n'))
else if (IChar2 = to_int('\\'))
then (CodePoint = to_int('\\'))
else throw("Error: unsupported escape \\" ++
from_char(det_from_int(IChar2)) ++
" at " ++ from_int(Line_no1) ++
":" ++ from_int(Column_no1))
)
)
else (CodePoint = IChar1)
).
:- pred check_char_lit_end(int::in, int::in, int::in,
inp_t::in, inp_t::out,
io::di, io::uo) is det.
check_char_lit_end(CloseQuote, Line_no, Column_no, !Inp, !IO) :-
get_ch(Ch1, !Inp, !IO),
Ch1 = {IChar1, _, _},
(
if (IChar1 = CloseQuote)
then true
else find_bad_char_lit_end(CloseQuote, Line_no, Column_no,
!Inp, !IO)
).
:- pred find_bad_char_lit_end(int::in, int::in, int::in,
inp_t::in, inp_t::out,
io::di, io::uo) is det.
find_bad_char_lit_end(CloseQuote, Line_no, Column_no, !Inp, !IO) :-
get_ch(Ch2, !Inp, !IO),
Ch2 = {IChar2, _, _},
(
if (IChar2 = CloseQuote)
then throw("Error: unsupported multicharacter literal " ++
" at " ++ from_int(Line_no) ++ ":" ++
from_int(Column_no))
else if (IChar2 = eof)
then throw("Error: end of input in character literal " ++
" at " ++ from_int(Line_no) ++ ":" ++
from_int(Column_no))
else find_bad_char_lit_end(CloseQuote, Line_no, Column_no,
!Inp, !IO)
).
:- pred scan_string_literal(toktup_t::out,
inp_t::in, inp_t::out,
io::di, io::uo) is det.
scan_string_literal(TokTup, !Inp, !IO) :-
get_ch(Ch, !Inp, !IO),
Ch = {OpenQuote, Line_no, Column_no},
CloseQuote = OpenQuote,
scan_string_lit_contents("", Str, CloseQuote,
Line_no, Column_no,
!Inp, !IO),
Arg = from_char(det_from_int(OpenQuote)) ++
Str ++ from_char(det_from_int(CloseQuote)),
TokTup = {token_STRING, Arg, Line_no, Column_no}.
:- pred scan_string_lit_contents(string::in, string::out, int::in,
int::in, int::in,
inp_t::in, inp_t::out,
io::di, io::uo) is det.
scan_string_lit_contents(Str0, Str, CloseQuote, Line_no, Column_no,
!Inp, !IO) :-
get_ch(Ch1, !Inp, !IO),
Ch1 = {IChar1, Line_no1, Column_no1},
(
if (IChar1 = CloseQuote)
then (Str = Str0)
else if (IChar1 = eof)
then throw("Error: end of input in string literal " ++
"starting at " ++ from_int(Line_no) ++ ":" ++
from_int(Column_no))
else if (IChar1 = to_int('\n'))
then throw("Error: end of line in string literal " ++
"starting at " ++ from_int(Line_no) ++ ":" ++
from_int(Column_no))
else if (IChar1 = to_int('\\'))
then
(
get_ch(Ch2, !Inp, !IO),
Ch2 = {IChar2, _, _},
(
if (IChar2 = to_int('n'))
then
(
Str1 = Str0 ++ "\\n",
scan_string_lit_contents(Str1, Str, CloseQuote,
Line_no, Column_no,
!Inp, !IO)
)
else if (IChar2 = to_int('\\'))
then
(
Str1 = Str0 ++ "\\\\",
scan_string_lit_contents(Str1, Str, CloseQuote,
Line_no, Column_no,
!Inp, !IO)
)
else if (IChar2 = eof)
then throw("Error: end of input in string literal " ++
"starting at " ++ from_int(Line_no) ++
":" ++ from_int(Column_no))
else if (IChar2 = to_int('\n'))
then throw("Error: end of line in string literal " ++
"starting at " ++ from_int(Line_no) ++
":" ++ from_int(Column_no))
else throw("Error: unsupported escape \\" ++
from_char(det_from_int(IChar2)) ++
" at " ++ from_int(Line_no1) ++
":" ++ from_int(Column_no1))
)
)
else
(
Char1 = det_from_int(IChar1),
Str1 = Str0 ++ from_char(Char1),
scan_string_lit_contents(Str1, Str, CloseQuote,
Line_no, Column_no, !Inp, !IO)
)
).
:- pred scan_identifier_or_reserved_word(toktup_t::out,
inp_t::in, inp_t::out,
io::di, io::uo) is det.
scan_identifier_or_reserved_word(TokTup, !Inp, !IO) :-
scan_integer_or_word(Str, Line_no, Column_no, !Inp, !IO),
(
if (Str = "if")
then (TokTup = {token_IF, Str, Line_no, Column_no})
else if (Str = "else")
then (TokTup = {token_ELSE, Str, Line_no, Column_no})
else if (Str = "while")
then (TokTup = {token_WHILE, Str, Line_no, Column_no})
else if (Str = "print")
then (TokTup = {token_PRINT, Str, Line_no, Column_no})
else if (Str = "putc")
then (TokTup = {token_PUTC, Str, Line_no, Column_no})
else (TokTup = {token_IDENTIFIER, Str, Line_no, Column_no})
).
:- pred scan_integer_literal(toktup_t::out, inp_t::in, inp_t::out,
io::di, io::uo) is det.
scan_integer_literal(TokTup, !Inp, !IO) :-
scan_integer_or_word(Str, Line_no, Column_no, !Inp, !IO),
(
if (not is_all_digits(Str))
then throw("Error: not a valid integer literal: " ++ Str)
else (TokTup = {token_INTEGER, Str, Line_no, Column_no})
).
:- pred scan_integer_or_word(string::out, int::out, int::out,
inp_t::in, inp_t::out,
io::di, io::uo) is det.
scan_integer_or_word(Str, Line_no, Column_no, !Inp, !IO) :-
get_ch({IChar, Line_no, Column_no}, !Inp, !IO),
(
if (IChar = eof)
then throw("internal error")
else
(
Char = det_from_int(IChar),
(if (not is_alnum_or_underscore(Char))
then throw("internal error")
else scan_int_or_word(from_char(Char), Str, !Inp, !IO))
)
).
:- pred scan_int_or_word(string::in, string::out,
inp_t::in, inp_t::out,
io::di, io::uo) is det.
scan_int_or_word(Str0, Str, !Inp, !IO) :-
get_ch(CharTup, !Inp, !IO),
{IChar, _, _} = CharTup,
(
if (IChar = eof)
then
(
push_back(CharTup, !Inp),
Str = Str0
)
else
(
Char = det_from_int(IChar),
(
if (not is_alnum_or_underscore(Char))
then
(
push_back(CharTup, !Inp),
Str = Str0
)
else scan_int_or_word(Str0 ++ from_char(Char), Str,
!Inp, !IO)
)
)
).
:- pred init(text_input_stream::in, inp_t::out) is det.
init(Inpf, Inp) :-
Inp = inp_t(Inpf, 1, 1, init).
:- pred get_ch(ch_t::out, inp_t::in, inp_t::out,
io::di, io::uo) is det.
get_ch(Ch, Inp0, Inp, !IO) :-
if (pop(Ch1, Inp0^pushback, Pushback))
then
(
Ch = Ch1,
Inp = (Inp0^pushback := Pushback)
)
else
(
inp_t(Inpf, Line_no, Column_no, Pushback) = Inp0,
read_char_unboxed(Inpf, Result, Char, !IO),
(
if (Result = ok)
then
(
Ch = {to_int(Char), Line_no, Column_no},
Inp =
(if (Char = ('\n'))
then inp_t(Inpf, Line_no + 1, 1, Pushback)
else inp_t(Inpf, Line_no, Column_no + 1, Pushback))
)
else
(
Ch = {eof, Line_no, Column_no},
Inp = Inp0
)
)
).
:- pred push_back(ch_t::in, inp_t::in, inp_t::out) is det.
push_back(Ch, Inp0, Inp) :-
Inp = (Inp0^pushback := push(Inp0^pushback, Ch)).
:- func eof = int is det.
eof = -1. |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Java | Java | public class Arguments {
public static void main(String[] args) {
System.out.println("There are " + args.length + " arguments given.");
for(int i = 0; i < args.length; i++)
System.out.println("The argument #" + (i+1) + " is " + args[i] + " and is at index " + i);
}
} |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #JavaScript | JavaScript | process.argv.forEach((val, index) => {
console.log(`${index}: ${val}`);
}); |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #dc | dc | [Making and discarding a string acts like a comment] sz |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Delphi | Delphi | // single line comment |
http://rosettacode.org/wiki/Conway%27s_Game_of_Life | Conway's Game of Life | The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 when alive, or 0 when dead, in an m-by-m (or m×m) square array of cells.
We calculate N - the sum of live cells in C's eight-location neighbourhood, then cell C is alive or dead in the next generation based on the following table:
C N new C
1 0,1 -> 0 # Lonely
1 4,5,6,7,8 -> 0 # Overcrowded
1 2,3 -> 1 # Lives
0 3 -> 1 # It takes three to give birth!
0 0,1,2,4,5,6,7,8 -> 0 # Barren
Assume cells beyond the boundary are always dead.
The "game" is actually a zero-player game, meaning that its evolution is determined by its initial state, needing no input from human players. One interacts with the Game of Life by creating an initial configuration and observing how it evolves.
Task
Although you should test your implementation on more complex examples such as the glider in a larger universe, show the action of the blinker (three adjoining cells in a row all alive), over three generations, in a 3 by 3 grid.
References
Its creator John Conway, explains the game of life. Video from numberphile on youtube.
John Conway Inventing Game of Life - Numberphile video.
Related task
Langton's ant - another well known cellular automaton.
| #Icon_and_Unicon | Icon and Unicon | global limit
procedure main(args)
n := args[1] | 50 # default is a 50x50 grid
limit := args[2] | &null # optional limit to number of generations
write("Enter the starting pattern, end with EOF")
grid := getInitialGrid(n)
play(grid)
end
# This procedure reads in the initial pattern, inserting it
# into an nXn grid of cells. The nXn grid also gets a
# new border of empty cells, which just makes the test simpler
# for determining what do with a cell on each generation.
# It would be better to let the user move the cursor and click
# on cells to create/delete living cells, but this version
# assumes a simple ASCII terminal.
procedure getInitialGrid(n)
static notBlank, allStars
initial {
notBlank := ~' '
allStars := repl("*",*notBlank)
}
g := [] # store as an array of strings
put(g,repl(" ",n))
while r := read() do { # read in rows of grid
r := left(r,n) # force each to length n
put(g," "||map(r,notBlank,allStars)||" ") # and making any life a '*'
}
while *g ~= (n+2) do
put(g,repl(" ",n))
return g
end
# Simple-minded procedure to 'play' Life from a starting grid.
procedure play(grid)
while not allDone(grid) do {
display(grid)
grid := onePlay(grid)
}
end
# Display the grid
procedure display(g)
write(repl("-",*g[1]))
every write(!g)
write(repl("-",*g[1]))
end
# Compute one generation of Life from the current one.
procedure onePlay(g)
ng := []
every put(ng, !g) # new generation starts as copy of old
every ng[r := 2 to *g-1][c := 2 to *g-1] := case sum(g,r,c) of {
3: "*" # cell lives (or is born)
2: g[r][c] # cell unchanged
default: " " # cell dead
}
return ng
end
# Return the number of living cells surrounding the current cell.
procedure sum(g,r,c)
cnt := 0
every (i := -1 to 1, j := -1 to 1) do
if ((i ~= 0) | (j ~= 0)) & (g[r+i][c+j] == "*") then cnt +:= 1
return cnt
end
# Check to see if all the cells have died or we've exceeded the
# number of allowed generations.
procedure allDone(g)
static count
initial count := 0
return ((count +:= 1) > \limit) | (trim(!g) == " ")
end |
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