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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.
| #Common_Lisp | Common Lisp | (if (= val 42)
"That is the answer to life, the universe and everything"
"Try again") ; the else clause here is optional |
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
| #Phix | Phix | with javascript_semantics
function allsame(sequence s)
for i=2 to length(s) do
if s[i]!=s[1] then return false end if
end for
return true
end function
function strict_order(sequence s)
for i=2 to length(s) do
if s[i]<=s[i-1] then return false end if
end for
return true
end function
procedure test(sequence s)
printf(1,"%-22V allsame:%5t, strict_order:%5t\n",{s,allsame(s),strict_order(s)})
end procedure
test({"AA","BB","CC"})
test({"AA","AA","AA"})
test({"AA","CC","BB"})
test({"AA","ACB","BB","CC"})
test({"single_element"})
|
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.
| #Gambas | Gambas | Public Sub Main()
Dim sInput As String[] = ["", "ABC", "ABC DEF", "ABC DEF G H"]
Dim sTemp As String
For Each sTemp In sInput
Print sTemp & " = ";
sTemp = Replace(sTemp, " ", ",")
If RInStr(sTemp, ",") > 0 Then
sTemp = Mid(sTemp, 1, RInStr(sTemp, ",") - 1) & " and " & Mid(sTemp, RInStr(sTemp, ",") + 1)
End If
sTemp = "{" & sTemp & "}"
Print sTemp
Next
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
| #Mercury | Mercury | :- module comb.
:- interface.
:- import_module list, int, bag.
:- pred choose(list(T)::in, int::in, bag(T)::out) is nondet.
:- pred choose_all(list(T)::in, int::in, list(list(T))::out) is det.
:- pred count_choices(list(T)::in, int::in, int::out) is det.
:- implementation.
:- import_module solutions.
choose(L, N, R) :- choose(L, N, bag.init, R).
:- pred choose(list(T)::in, int::in, bag(T)::in, bag(T)::out) is nondet.
choose(L, N, !R) :-
( N = 0 ->
true
;
member(X, L),
bag.insert(!.R, X, !:R),
choose(L, N - 1, !R)
).
choose_all(L, N, R) :-
solutions(choose(L, N), R0),
list.map(bag.to_list, R0, R).
count_choices(L, N, Count) :-
aggregate(choose(L, N), count, 0, Count).
:- pred count(T::in, int::in, int::out) is det.
count(_, N0, N) :- N0 + 1 = 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
| #Nim | Nim | import sugar, sequtils
proc combsReps[T](lst: seq[T], k: int): seq[seq[T]] =
if k == 0:
@[newSeq[T]()]
elif lst.len == 0:
@[]
else:
lst.combsReps(k - 1).map((x: seq[T]) => lst[0] & x) &
lst[1 .. ^1].combsReps(k)
echo(@["iced", "jam", "plain"].combsReps(2))
echo toSeq(1..10).combsReps(3).len |
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
| #Stata | Stata | real scalar comb1(n, k) {
return(exp(lnfactorial(n)-lnfactorial(k)-lnfactorial(n-k)))
}
real scalar perm(n, k) {
return(exp(lnfactorial(n)-lnfactorial(n-k)))
} |
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
| #Swift | Swift | import BigInt
func permutations(n: Int, k: Int) -> BigInt {
let l = n - k + 1
guard l <= n else {
return 1
}
return (l...n).reduce(BigInt(1), { $0 * BigInt($1) })
}
func combinations(n: Int, k: Int) -> BigInt {
let fact = {() -> BigInt in
guard k > 1 else {
return 1
}
return (2...k).map({ BigInt($0) }).reduce(1, *)
}()
return permutations(n: n, k: k) / fact
}
print("Sample of permutations from 1 to 12")
for i in 1...12 {
print("\(i) P \(i / 3) = \(permutations(n: i, k: i / 3))")
}
print("\nSample of combinations from 10 to 60")
for i in stride(from: 10, through: 60, by: 10) {
print("\(i) C \(i / 3) = \(combinations(n: i, k: i / 3))")
}
print("\nSample of permutations from 5 to 15,000")
for i in [5, 50, 500, 1000, 5000, 15000] {
let k = i / 3
let res = permutations(n: i, k: k).description
let extra = res.count > 40 ? "... (\(res.count - 40) more digits)" : ""
print("\(i) P \(k) = \(res.prefix(40))\(extra)")
}
print("\nSample of combinations from 100 to 1000")
for i in stride(from: 100, through: 1000, by: 100) {
let k = i / 3
let res = combinations(n: i, k: k).description
let extra = res.count > 40 ? "... (\(res.count - 40) more digits)" : ""
print("\(i) C \(k) = \(res.prefix(40))\(extra)")
} |
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
| #Nim | Nim |
import re, strformat, strutils
type
TokenKind = enum
tkUnknown = "UNKNOWN_TOKEN",
tkMul = "Op_multiply",
tkDiv = "Op_divide",
tkMod = "Op_mod",
tkAdd = "Op_add",
tkSub = "Op_subtract",
tkNeg = "Op_negate",
tkLt = "Op_less",
tkLte = "Op_lessequal",
tkGt = "Op_greater",
tkGte = "Op_greaterequal",
tkEq = "Op_equal",
tkNeq = "Op_notequal",
tkNot = "Op_not",
tkAsgn = "Op_assign",
tkAnd = "Op_and",
tkOr = "Op_or",
tkLpar = "LeftParen",
tkRpar = "RightParen",
tkLbra = "LeftBrace",
tkRbra = "RightBrace",
tkSmc = "Semicolon",
tkCom = "Comma",
tkIf = "Keyword_if",
tkElse = "Keyword_else",
tkWhile = "Keyword_while",
tkPrint = "Keyword_print",
tkPutc = "Keyword_putc",
tkId = "Identifier",
tkInt = "Integer",
tkChar = "Integer",
tkStr = "String",
tkEof = "End_of_input"
Token = object
kind: TokenKind
value: string
TokenAnn = object
## Annotated token with messages for compiler
token: Token
line, column: int
proc getSymbols(table: openArray[(char, TokenKind)]): seq[char] =
result = newSeq[char]()
for ch, tokenKind in items(table):
result.add ch
const
tkSymbols = { # single-char tokens
'*': tkMul,
'%': tkMod,
'+': tkAdd,
'-': tkSub,
'(': tkLpar,
')': tkRpar,
'{': tkLbra,
'}': tkRbra,
';': tkSmc,
',': tkCom,
'/': tkDiv, # the comment case /* ... */ is handled in `stripUnimportant`
}
symbols = getSymbols(tkSymbols)
proc findTokenKind(table: openArray[(char, TokenKind)]; needle: char):
TokenKind =
for ch, tokenKind in items(table):
if ch == needle: return tokenKind
tkUnknown
proc stripComment(text: var string, lineNo, colNo: var int) =
var matches: array[1, string]
if match(text, re"\A(/\*[\s\S]*?\*/)", matches):
text = text[matches[0].len..^1]
for s in matches[0]:
if s == '\n':
inc lineNo
colNo = 1
else:
inc colNo
proc stripUnimportant(text: var string; lineNo, colNo: var int) =
while true:
if text.len == 0: return
elif text[0] == '\n':
inc lineNo
colNo = 1
text = text[1..^1]
elif text[0] == ' ':
inc colNo
text = text[1..^1]
elif text.len >= 2 and text[0] == '/' and text[1] == '*':
stripComment(text, lineNo, colNo)
else: return
proc lookAhead(ch1, ch2: char, tk1, tk2: TokenKind): (TokenKind, int) =
if ch1 == ch2: (tk1, 2)
else: (tk2, 1)
proc consumeToken(text: var string; tkl: var int): Token =
## Return token removing it from the `text` and write its length to
## `tkl`. If the token can not be defined, return `tkUnknown` as a
## token, shrink text by 1 and write 1 to its length.
var
matches: array[1, string]
tKind: TokenKind
val: string
if text.len == 0:
(tKind, tkl) = (tkEof, 0)
# Simple characters
elif text[0] in symbols: (tKind, tkl) = (tkSymbols.findTokenKind(text[0]), 1)
elif text[0] == '<': (tKind, tkl) = lookAhead(text[1], '=', tkLte, tkLt)
elif text[0] == '>': (tKind, tkl) = lookAhead(text[1], '=', tkGte, tkGt)
elif text[0] == '=': (tKind, tkl) = lookAhead(text[1], '=', tkEq, tkAsgn)
elif text[0] == '!': (tKind, tkl) = lookAhead(text[1], '=', tkNeq, tkNot)
elif text[0] == '&': (tKind, tkl) = lookAhead(text[1], '&', tkAnd, tkUnknown)
elif text[0] == '|': (tKind, tkl) = lookAhead(text[1], '|', tkOr, tkUnknown)
# Keywords
elif match(text, re"\Aif\b"): (tKind, tkl) = (tkIf, 2)
elif match(text, re"\Aelse\b"): (tKind, tkl) = (tkElse, 4)
elif match(text, re"\Awhile\b"): (tKind, tkl) = (tkWhile, 5)
elif match(text, re"\Aprint\b"): (tKind, tkl) = (tkPrint, 5)
elif match(text, re"\Aputc\b"): (tKind, tkl) = (tkPutc, 4)
# Literals and identifiers
elif match(text, re"\A([0-9]+)", matches):
(tKind, tkl) = (tkInt, matches[0].len)
val = matches[0]
elif match(text, re"\A([_a-zA-Z][_a-zA-Z0-9]*)", matches):
(tKind, tkl) = (tkId, matches[0].len)
val = matches[0]
elif match(text, re"\A('(?:[^'\n]|\\\\|\\n)')", matches):
(tKind, tkl) = (tkChar, matches[0].len)
val = case matches[0]
of r"' '": $ord(' ')
of r"'\n'": $ord('\n')
of r"'\\'": $ord('\\')
else: $ord(matches[0][1]) # "'a'"[1] == 'a'
elif match(text, re"\A(""[^""\n]*"")", matches):
(tKind, tkl) = (tkStr, matches[0].len)
val = matches[0]
else: (tKind, tkl) = (tkUnknown, 1)
text = text[tkl..^1]
Token(kind: tKind, value: val)
proc tokenize*(text: string): seq[TokenAnn] =
result = newSeq[TokenAnn]()
var
lineNo, colNo: int = 1
text = text
token: Token
tokenLength: int
while text.len > 0:
stripUnimportant(text, lineNo, colNo)
token = consumeToken(text, tokenLength)
result.add TokenAnn(token: token, line: lineNo, column: colNo)
inc colNo, tokenLength
proc output*(s: seq[TokenAnn]): string =
var
tokenKind: TokenKind
value: string
line, column: int
for tokenAnn in items(s):
line = tokenAnn.line
column = tokenAnn.column
tokenKind = tokenAnn.token.kind
value = tokenAnn.token.value
result.add(
fmt"{line:>5}{column:>7} {tokenKind:<15}{value}"
.strip(leading = false) & "\n")
when isMainModule:
import os
let input = if paramCount() > 0: readFile paramStr(1)
else: readAll stdin
echo input.tokenize.output
|
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"
| #jq | jq | $ARGS.positional contains an array of the positional arguments as JSON strings
|
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"
| #Jsish | Jsish | #!/usr/local/bin/jsish
puts(Info.argv0());
puts(console.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"
| #Julia | Julia | using Printf
prog = Base.basename(Base.source_path())
println(prog, "'s command-line arguments are:")
for s in ARGS
println(" ", s)
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.)
| #Deluge | Deluge | // 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.)
| #Dragon | Dragon | // This is 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.
| #INTERCAL | INTERCAL | pad=: 0,0,~0,.0,.~]
life=: (3 3 (+/ e. 3+0,4&{)@,;._3 ])@pad
NB. the above could also be a one-line solution:
life=: (3 3 (+/ e. 3+0,4&{)@,;._3 ])@(0,0,~0,.0,.~])
|
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.
| #Computer.2Fzero_Assembly | Computer/zero Assembly | if (condition)
{
// Some Task
}
if (condition)
{
// Some Task
}
else if (condition2)
{
// Some Task
}
else
{
// Some Task
} |
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
| #Phixmonti | Phixmonti | include ..\Utilitys.pmt
( "alpha" "beta" "gamma" "delta" "epsilon" "zeta"
"eta" "theta" "iota" "kappa" "lambda" "mu" )
dup dup sort == /# put 0 (false) in the pile, indicating that they are not in ascending order #/
drop /# discard the result #/
dup len swap 1 get rot repeat == /# put 0 (false) in the pile, indicating that they are not repeated 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
| #Picat | Picat | main =>
Lists = [["AA","BB","CC"],
["AA","AA","AA"],
["AA","CC","BB"],
["AA","ACB","BB","CC"],
["single_element"],
[]],
foreach(L in Lists)
Same = all_same(L).cond(true,false),
Sorted = sorted(L).cond(true,false),
printf("%-18w all_same:%-5w sorted:%-5w\n",L,Same,Sorted)
end.
all_same([]).
all_same([_]).
all_same([A,B|Rest]) :-
A == B,
all_same([B|Rest]). |
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.
| #Go | Go | package main
import (
"fmt"
"strings"
)
func q(s []string) string {
switch len(s) {
case 0:
return "{}"
case 1:
return "{" + s[0] + "}"
case 2:
return "{" + s[0] + " and " + s[1] + "}"
default:
return "{" +
strings.Join(s[:len(s)-1], ", ") +
" and " +
s[len(s)-1] +
"}"
}
}
func main() {
fmt.Println(q([]string{}))
fmt.Println(q([]string{"ABC"}))
fmt.Println(q([]string{"ABC", "DEF"}))
fmt.Println(q([]string{"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
| #OCaml | OCaml | let rec combs_with_rep k xxs =
match k, xxs with
| 0, _ -> [[]]
| _, [] -> []
| k, x::xs ->
List.map (fun ys -> x::ys) (combs_with_rep (k-1) xxs)
@ combs_with_rep k xs |
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
| #PARI.2FGP | PARI/GP | ways(k,v,s=[])={
if(k==0,return([]));
if(k==1,return(vector(#v,i,concat(s,[v[i]]))));
if(#v==1,return(ways(k-1,v,concat(s,v))));
my(u=vecextract(v,2^#v-2));
concat(ways(k-1,v,concat(s,[v[1]])),ways(k,u,s))
};
xc(k,v)=binomial(#v+k-1,k);
ways(2, ["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
| #Tcl | Tcl | # Exact integer versions
proc tcl::mathfunc::P {n k} {
set t 1
for {set i $n} {$i > $n-$k} {incr i -1} {
set t [expr {$t * $i}]
}
return $t
}
proc tcl::mathfunc::C {n k} {
set t [P $n $k]
for {set i $k} {$i > 1} {incr i -1} {
set t [expr {$t / $i}]
}
return $t
}
# Floating point versions using the Gamma function
package require math
proc tcl::mathfunc::lnGamma n {math::ln_Gamma $n}
proc tcl::mathfunc::fP {n k} {
expr {exp(lnGamma($n+1) - lnGamma($n-$k+1))}
}
proc tcl::mathfunc::fC {n k} {
expr {exp(lnGamma($n+1) - lnGamma($n-$k+1) - lnGamma($k+1))}
} |
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
| #ObjectIcon | ObjectIcon | # -*- ObjectIcon -*-
#
# The Rosetta Code lexical analyzer in Object Icon. Based upon the ATS
# implementation.
#
# Usage: lex [INPUTFILE [OUTPUTFILE]]
# If INPUTFILE or OUTPUTFILE is "-" or missing, then standard input
# or standard output is used, respectively. *)
#
import io
$define EOF -1
$define TOKEN_ELSE 0
$define TOKEN_IF 1
$define TOKEN_PRINT 2
$define TOKEN_PUTC 3
$define TOKEN_WHILE 4
$define TOKEN_MULTIPLY 5
$define TOKEN_DIVIDE 6
$define TOKEN_MOD 7
$define TOKEN_ADD 8
$define TOKEN_SUBTRACT 9
$define TOKEN_NEGATE 10
$define TOKEN_LESS 11
$define TOKEN_LESSEQUAL 12
$define TOKEN_GREATER 13
$define TOKEN_GREATEREQUAL 14
$define TOKEN_EQUAL 15
$define TOKEN_NOTEQUAL 16
$define TOKEN_NOT 17
$define TOKEN_ASSIGN 18
$define TOKEN_AND 19
$define TOKEN_OR 20
$define TOKEN_LEFTPAREN 21
$define TOKEN_RIGHTPAREN 22
$define TOKEN_LEFTBRACE 23
$define TOKEN_RIGHTBRACE 24
$define TOKEN_SEMICOLON 25
$define TOKEN_COMMA 26
$define TOKEN_IDENTIFIER 27
$define TOKEN_INTEGER 28
$define TOKEN_STRING 29
$define TOKEN_END_OF_INPUT 30
global whitespace
global ident_start
global ident_continuation
procedure main(args)
local inpf, outf
local pushback_buffer, inp, pushback
initial {
whitespace := ' \t\v\f\r\n'
ident_start := '_' ++ &letters
ident_continuation := ident_start ++ &digits
}
inpf := FileStream.stdin
outf := FileStream.stdout
if 1 <= *args & args[1] ~== "-" then {
inpf := FileStream(args[1], FileOpt.RDONLY) | stop(&why)
}
if 2 <= *args & args[2] ~== "-" then {
outf := FileStream(args[2], ior(FileOpt.WRONLY,
FileOpt.TRUNC,
FileOpt.CREAT)) | stop(&why)
}
pushback_buffer := []
inp := create inputter(inpf, pushback_buffer)
pushback := create repeat push(pushback_buffer, \@&source)
@pushback # The first invocation does nothing.
scan_text(outf, inp, pushback)
end
procedure scan_text(outf, inp, pushback)
local ch
while /ch | ch[1] ~=== EOF do {
skip_spaces_and_comments(inp, pushback)
ch := @inp
if ch[1] === EOF then {
print_token(outf, [TOKEN_END_OF_INPUT, "", ch[2], ch[3]])
} else {
ch @pushback
print_token(outf, get_next_token(inp, pushback))
}
}
end
procedure get_next_token(inp, pushback)
local ch, ch1
local ln, cn
skip_spaces_and_comments(inp, pushback)
ch := @inp
ln := ch[2] # line number
cn := ch[3] # column number
case ch[1] of {
"," : return [TOKEN_COMMA, ",", ln, cn]
";" : return [TOKEN_SEMICOLON, ";", ln, cn]
"(" : return [TOKEN_LEFTPAREN, "(", ln, cn]
")" : return [TOKEN_RIGHTPAREN, ")", ln, cn]
"{" : return [TOKEN_LEFTBRACE, "{", ln, cn]
"}" : return [TOKEN_RIGHTBRACE, "}", ln, cn]
"*" : return [TOKEN_MULTIPLY, "*", ln, cn]
"/" : return [TOKEN_DIVIDE, "/", ln, cn]
"%" : return [TOKEN_MOD, "%", ln, cn]
"+" : return [TOKEN_ADD, "+", ln, cn]
"-" : return [TOKEN_SUBTRACT, "-", ln, cn]
"<" : {
ch1 := @inp
if ch1[1] === "=" then {
return [TOKEN_LESSEQUAL, "<=", ln, cn]
} else {
ch1 @pushback
return [TOKEN_LESS, "<", ln, cn]
}
}
">" : {
ch1 := @inp
if ch1[1] === "=" then {
return [TOKEN_GREATEREQUAL, ">=", ln, cn]
} else {
ch1 @pushback
return [TOKEN_GREATER, ">", ln, cn]
}
}
"=" : {
ch1 := @inp
if ch1[1] === "=" then {
return [TOKEN_EQUAL, "==", ln, cn]
} else {
ch1 @pushback
return [TOKEN_ASSIGN, "=", ln, cn]
}
}
"!" : {
ch1 := @inp
if ch1[1] === "=" then {
return [TOKEN_NOTEQUAL, "!=", ln, cn]
} else {
ch1 @pushback
return [TOKEN_NOT, "!", ln, cn]
}
}
"&" : {
ch1 := @inp
if ch1[1] === "&" then {
return [TOKEN_AND, "&&", ln, cn]
} else {
unexpected_character(ln, cn, ch)
}
}
"|" : {
ch1 := @inp
if ch1[1] === "|" then {
return [TOKEN_OR, "||", ln, cn]
} else {
unexpected_character(ln, cn, ch)
}
}
"\"" : {
ch @pushback
return scan_string_literal(inp)
}
"'" : {
ch @pushback
return scan_character_literal(inp, pushback)
}
default : {
if any(&digits, ch[1]) then {
ch @pushback
return scan_integer_literal(inp, pushback)
} else if any(ident_start, ch[1]) then {
ch @pushback
return scan_identifier_or_reserved_word (inp, pushback)
} else {
unexpected_character(ln, cn, ch)
}
}
}
end
procedure scan_identifier_or_reserved_word(inp, pushback)
local ch
local s
local line_no, column_no
s := ""
ch := @inp
line_no := ch[2]
column_no := ch[3]
while EOF ~=== ch[1] & any(ident_continuation, ch[1]) do {
s ||:= ch[1]
ch := @inp
}
ch @pushback
return reserved_word_lookup (s, line_no, column_no)
end
procedure scan_integer_literal(inp, pushback)
local ch
local s
local line_no, column_no
s := ""
ch := @inp
line_no := ch[2]
column_no := ch[3]
while EOF ~=== ch[1] & any(ident_continuation, ch[1]) do {
s ||:= ch[1]
ch := @inp
}
ch @pushback
not upto(~&digits, s) | invalid_integer_literal(line_no, column_no, s)
return [TOKEN_INTEGER, s, line_no, column_no]
end
procedure scan_character_literal(inp, pushback)
local ch, ch1
local close_quote
local toktup
local line_no, column_no
ch := @inp # The opening quote.
close_quote := ch[1] # Same as the opening quote.
ch @pushback
line_no := ch[2]
column_no := ch[3]
toktup := scan_character_literal_without_checking_end(inp)
ch1 := @inp
if ch1[1] ~=== close_quote then {
repeat {
case ch1[1] of {
EOF : unterminated_character_literal(line_no, column_no)
close_quote : multicharacter_literal(line_no, column_no)
default : ch1 := @inp
}
}
}
return toktup
end
procedure scan_character_literal_without_checking_end(inp)
local ch, ch1, ch2
ch := @inp # The opening quote.
ch1 := @inp
EOF ~=== ch1[1] | unterminated_character_literal(ch[2], ch[3])
if ch1[1] == "\\" then {
ch2 := @inp
EOF ~=== ch2[1] | unterminated_character_literal(ch[2], ch[3])
case ch2[1] of {
"n" : return [TOKEN_INTEGER, string(ord("\n")), ch[2], ch[3]]
"\\" : return [TOKEN_INTEGER, string(ord("\\")), ch[2], ch[3]]
default : unsupported_escape(ch1[2], ch1[3], ch2)
}
} else {
return [TOKEN_INTEGER, string(ord(ch1[1])), ch[2], ch[3]]
}
end
procedure scan_string_literal(inp)
local ch, ch1, ch2
local line_no, column_no
local close_quote
local s
local retval
ch := @inp # The opening quote
close_quote := ch[1] # Same as the opening quote.
line_no := ch[2]
column_no := ch[3]
s := ch[1]
until \retval do {
ch1 := @inp
ch1[1] ~=== EOF |
unterminated_string_literal (line_no, column_no,
"end of input")
ch1[1] ~== "\n" |
unterminated_string_literal (line_no, column_no,
"end of line")
if ch1[1] == close_quote then {
retval := [TOKEN_STRING, s || close_quote, line_no, column_no]
} else if ch1[1] ~== "\\" then {
s ||:= ch1[1]
} else {
ch2 := @inp
EOF ~=== ch2[1] | unsupported_escape(line_no, column_no, ch2)
case ch2[1] of {
"n" : s ||:= "\\n"
"\\" : s ||:= "\\\\"
default : unsupported_escape(line_no, column_no, ch2)
}
}
}
return retval
end
procedure skip_spaces_and_comments(inp, pushback)
local ch, ch1
repeat {
ch := @inp
(EOF === ch[1]) & { ch @pushback; return }
if not any(whitespace, ch[1]) then {
(ch[1] == "/") | { ch @pushback; return }
(ch1 := @inp) | { ch @pushback; return }
(ch1[1] == "*") | { ch1 @pushback; ch @pushback; return }
scan_comment(inp, ch[2], ch[3])
}
}
end
procedure scan_comment(inp, line_no, column_no)
local ch, ch1
until (\ch)[1] == "*" & (\ch1)[1] == "/" do {
ch := @inp
(EOF === ch[1]) & unterminated_comment(line_no, column_no)
if ch[1] == "*" then {
ch1 := @inp
(EOF === ch[1]) & unterminated_comment(line_no, column_no)
}
}
return
end
procedure reserved_word_lookup(s, line_no, column_no)
# Lookup is by an extremely simple perfect hash.
static reserved_words
static reserved_word_tokens
local hashval, token, toktup
initial {
reserved_words := ["if", "print", "else",
"", "putc", "",
"", "while", ""]
reserved_word_tokens :=
[TOKEN_IF, TOKEN_PRINT, TOKEN_ELSE,
TOKEN_IDENTIFIER, TOKEN_PUTC, TOKEN_IDENTIFIER,
TOKEN_IDENTIFIER, TOKEN_WHILE, TOKEN_IDENTIFIER]
}
if *s < 2 then {
toktup := [TOKEN_IDENTIFIER, s, line_no, column_no]
} else {
hashval := ((ord(s[1]) + ord(s[2])) % (*reserved_words)) + 1
token := reserved_word_tokens[hashval]
if token = TOKEN_IDENTIFIER | s ~== reserved_words[hashval] then {
toktup := [TOKEN_IDENTIFIER, s, line_no, column_no]
} else {
toktup := [token, s, line_no, column_no]
}
}
return toktup
end
procedure print_token(outf, toktup)
static token_names
local s_line, s_column
initial {
token_names := ["Keyword_else",
"Keyword_if",
"Keyword_print",
"Keyword_putc",
"Keyword_while",
"Op_multiply",
"Op_divide",
"Op_mod",
"Op_add",
"Op_subtract",
"Op_negate",
"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",
"Identifier",
"Integer",
"String",
"End_of_input"]
}
/outf := FileStream.stdout
s_line := string(toktup[3])
s_column := string(toktup[4])
writes(outf, right (s_line, max(5, *s_line)))
writes(outf, " ")
writes(outf, right (s_column, max(5, *s_column)))
writes(outf, " ")
writes(outf, token_names[toktup[1] + 1])
case toktup[1] of {
TOKEN_IDENTIFIER : writes(outf, " ", toktup[2])
TOKEN_INTEGER : writes(outf, " ", toktup[2])
TOKEN_STRING : writes(outf, " ", toktup[2])
}
write(outf)
return
end
procedure inputter(inpf, pushback_buffer)
local buffer
local line_no, column_no
local c
buffer := ""
line_no := 1
column_no := 1
repeat {
buffer? {
until *pushback_buffer = 0 & pos(0) do {
if *pushback_buffer ~= 0 then {
suspend pop(pushback_buffer)
} else {
c := move(1)
suspend [c, line_no, column_no]
if c == "\n" then {
line_no +:= 1
column_no := 1
} else {
column_no +:= 1
}
}
}
}
(buffer := reads(inpf, 2048)) |
suspend [EOF, line_no, column_no]
}
end
procedure unterminated_comment(line_no, column_no)
error("unterminated comment starting at ",
line_no, ":", column_no)
end
procedure unexpected_character(line_no, column_no, ch)
error("unexpected character '", ch[1], "' starting at ",
line_no, ":", column_no)
end
procedure unterminated_string_literal (line_no, column_no, cause)
error("unterminated string literal (", cause, ") starting at ",
line_no, ":", column_no)
end
procedure unsupported_escape (line_no, column_no, ch)
if ch[1] === EOF then {
error("unexpected \\ at end of input",
" starting at ", line_no, ":", column_no)
} else {
error("unsupported escape \\", ch[1],
" starting at ", line_no, ":", column_no)
}
end
procedure invalid_integer_literal(line_no, column_no, s)
error("invalid integer literal ", s,
" starting at ", line_no, ":", column_no)
end
procedure unterminated_character_literal(line_no, column_no)
error("unterminated character literal starting at ",
line_no, ":", column_no)
end
procedure multicharacter_literal(line_no, column_no)
error("unsupported multicharacter literal starting at ",
line_no, ":", column_no)
end
procedure error(args[])
write!([FileStream.stderr] ||| args)
exit(1)
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"
| #Klong | Klong |
.p'.a
|
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"
| #Kotlin | Kotlin | fun main(args: Array<String>) {
println("There are " + args.size + " arguments given.")
args.forEachIndexed { i, a -> println("The argument #${i+1} is $a and is at index $i") }
} |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Lasso | Lasso | #!/usr/bin/lasso9
iterate($argv) => {
stdoutnl("Argument " + loop_count + ": " + loop_value)
} |
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.)
| #DWScript | DWScript | (* This is a comment.
It may extend across multiple lines. *)
{ Alternatively curly braces
can be used. }
/* C-style multi-line comments
are supported */
// and single-line C++ style comments too |
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.)
| #Dyalect | Dyalect | /* This is a
multi-line comment */
//This is a 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.
| #J | J | pad=: 0,0,~0,.0,.~]
life=: (3 3 (+/ e. 3+0,4&{)@,;._3 ])@pad
NB. the above could also be a one-line solution:
life=: (3 3 (+/ e. 3+0,4&{)@,;._3 ])@(0,0,~0,.0,.~])
|
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.
| #Crack | Crack | if (condition)
{
// Some Task
}
if (condition)
{
// Some Task
}
else if (condition2)
{
// Some Task
}
else
{
// Some Task
} |
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
| #PicoLisp | PicoLisp | (= "AA" "AA" "AA")
-> T
(= "AA" "AA" "Aa")
-> NIL
(< "AA" "AA")
-> NIL
(< "AA" "Aa")
-> T
(< "1" "A" "B" "Z" "c" )
-> T
(> "A" "B" "Z" "C")
-> 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
| #PL.2FI | PL/I | *process source xref attributes or(!);
/*--------------------------------------------------------------------
* 01.07.2014 Walter Pachl
*-------------------------------------------------------------------*/
clist: Proc Options(main);
Dcl (hbound) Builtin;
Dcl sysprint Print;
Dcl abc(3) Char(2) Init('AA','BB','CC');
Dcl aaa(3) Char(2) Init('AA','AA','AA');
Dcl acb(3) Char(2) Init('AA','CC','BB');
Call test('ABC',ABC);
Call test('AAA',AAA);
Call test('ACB',ACB);
test: Procedure(name,x);
Dcl name Char(*);
Dcl x(*) Char(*);
Dcl (all_equal,increasing) Bit(1) Init('1'b);
Dcl (i,i1) Bin Fixed(31);
Dcl txt Char(50) Var;
Do i=1 To hbound(x)-1 While(all_equal ! increasing);
i1=i+1;
Select;
When(x(i1)=x(i)) increasing='0'b;
When(x(i1)<x(i)) Do;
increasing='0'b;
all_equal='0'b;
End;
Otherwise /* x(i1)>x(i) */
all_equal='0'b;
End;
End;
Select;
When(all_equal) txt='all elements are equal';
When(increasing) txt='elements are in increasing order';
Otherwise txt='neither equal nor in increasing order';
End;
Put Skip List(name!!': '!!txt);
End;
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.
| #Groovy | Groovy | def commaQuibbling = { it.size() < 2 ? "{${it.join(', ')}}" : "{${it[0..-2].join(', ')} and ${it[-1]}}" } |
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.
| #Haskell | Haskell | quibble ws = "{" ++ quibbles ws ++ "}"
where quibbles [] = ""
quibbles [a] = a
quibbles [a,b] = a ++ " and " ++ b
quibbles (a:bs) = a ++ ", " ++ quibbles bs
main = mapM_ (putStrLn . quibble) $
[[], ["ABC"], ["ABC", "DEF"], ["ABC", "DEF", "G", "H"]] ++
(map words ["One two three four", "Me myself I", "Jack Jill", "Loner" ])
|
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
| #Pascal | Pascal | program CombWithRep;
//combinations with repetitions
//Limit = count of elements
//Maxval = value of top , lowest is always 0
//so 0..Maxvalue => maxValue+1 elements
{$IFDEF FPC}
// {$R+,O+}
{$MODE DELPHI}{$OPTIMIZATION ON,ALL}{$COPERATORS ON}
{$ELSE}{$APPTYPE CONSOLE}{$ENDIF}
uses
SysUtils;//GetTickCount64
var
CombIdx: array of byte;
function InitCombIdx(ElemCount: Int32): pbyte;
begin
setlength(CombIdx, ElemCount + 1);
Fillchar(CombIdx[0], sizeOf(CombIdx[0]) * (ElemCount + 1), #0);
Result := @CombIdx[0];
end;
function NextCombWithRep(pComb: pByte; MaxVal, ElemCount: UInt32): boolean;
var
i, dgt: NativeInt;
begin
i := -1;
repeat
i += 1;
dgt := pComb[i];
if dgt < MaxVal then
break;
until i > ElemCount;
Result := i >= ElemCount;
dgt +=1;
repeat
pComb[i] := dgt;
i -= 1;
until i < 0;
end;
procedure GetDoughnuts(ElemCount: NativeInt);
const
doughnuts: array[0..2] of string = ('iced', 'jam', 'plain');
var
pComb: pByte;
MaxVal, i: Uint32;
begin
if ElemCount < 1 then
EXIT;
MaxVal := High(doughnuts);
writeln('Getting ', ElemCount, ' elements of ', MaxVal + 1, ' different');
pComb := InitCombIdx(ElemCount);
repeat
Write('[');
for i := 0 to ElemCount - 2 do
Write(pComb[i], ',');
Write(pComb[ElemCount - 1], ']');
Write('{');
for i := 0 to ElemCount - 2 do
Write(doughnuts[pComb[i]], ',');
Write(doughnuts[pComb[ElemCount - 1]], '}');
until NextCombWithRep(pComb, MaxVal, ElemCount);
writeln(#10);
end;
procedure Check(ElemCount: Int32; ElemRange: Uint32);
var
pComb: pByte;
T0: int64;
rec_cnt: NativeInt;
begin
T0 := GetTickCount64;
rec_cnt := 0;
ElemRange -= 1;
pComb := InitCombIdx(ElemCount);
repeat
Inc(rec_cnt);
until NextCombWithRep(pComb, ElemRange, ElemCount);
T0 := GetTickCount64 - T0;
writeln('Getting ', ElemCount, ' elements of ', ElemRange + 1, ' different');
writeln(rec_cnt: 10, t0: 10,' ms');
end;
begin
GetDoughnuts(2);
GetDoughnuts(3);
Check(3, 10);
Check(9, 10);
Check(15, 16);
{$IFDEF WINDOWS}
readln;
{$ENDIF}
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
| #VBScript | VBScript | ' Combinations and permutations - vbs - 10/04/2017
dim i,j
Wscript.StdOut.WriteLine "-- Long Integer - Permutations - from 1 to 12"
for i=1 to 12
for j=1 to i
Wscript.StdOut.Write "P(" & i & "," & j & ")=" & perm(i,j) & " "
next 'j
Wscript.StdOut.WriteLine ""
next 'i
Wscript.StdOut.WriteLine "-- Float integer - Combinations from 10 to 60"
for i=10 to 60 step 10
for j=1 to i step i\5
Wscript.StdOut.Write "C(" & i & "," & j & ")=" & comb(i,j) & " "
next 'j
Wscript.StdOut.WriteLine ""
next 'i
Wscript.StdOut.WriteLine "-- Float integer - Permutations from 5000 to 15000"
for i=5000 to 15000 step 5000
for j=10 to 70 step 20
Wscript.StdOut.Write "C(" & i & "," & j & ")=" & perm(i,j) & " "
next 'j
Wscript.StdOut.WriteLine ""
next 'i
Wscript.StdOut.WriteLine "-- Float integer - Combinations from 200 to 1000"
for i=200 to 1000 step 200
for j=20 to 100 step 20
Wscript.StdOut.Write "P(" & i & "," & j & ")=" & comb(i,j) & " "
next 'j
Wscript.StdOut.WriteLine ""
next 'i
function perm(x,y)
dim i,z
z=1
for i=x-y+1 to x
z=z*i
next 'i
perm=z
end function 'perm
function fact(x)
dim i,z
z=1
for i=2 to x
z=z*i
next 'i
fact=z
end function 'fact
function comb(byval x,byval y)
if y>x then
comb=0
elseif x=y then
comb=1
else
if x-y<y then y=x-y
comb=perm(x,y)/fact(y)
end if
end function 'comb |
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
| #Visual_Basic_.NET | Visual Basic .NET | ' Combinations and permutations - 10/04/2017
Imports System.Numerics 'BigInteger
Module CombPermRc
Sub Main()
Dim i, j As Long
For i = 1 To 12
For j = 1 To i
Console.Write("P(" & i & "," & j & ")=" & PermBig(i, j).ToString & " ")
Next j
Console.WriteLine("")
Next i
Console.WriteLine("--")
For i = 10 To 60 Step 10
For j = 1 To i Step i \ 5
Console.Write("C(" & i & "," & j & ")=" & CombBig(i, j).ToString & " ")
Next j
Console.WriteLine("")
Next i
Console.WriteLine("--")
For i = 5000 To 15000 Step 5000
For j = 4000 To 5000 Step 1000
Console.Write("P(" & i & "," & j & ")=" & PermBig(i, j).ToString("E") & " ")
Next j
Console.WriteLine("")
Next i
Console.WriteLine("--")
For i = 5000 To 15000 Step 5000
For j = 4000 To 5000 Step 1000
Console.Write("C(" & i & "," & j & ")=" & CombBig(i, j).ToString("E") & " ")
Next j
Console.WriteLine("")
Next i
Console.WriteLine("--")
i = 5000 : j = 4000
Console.WriteLine("C(" & i & "," & j & ")=" & CombBig(i, j).ToString)
End Sub 'Main
Function PermBig(x As Long, y As Long) As BigInteger
Dim i As Long, z As BigInteger
z = 1
For i = x - y + 1 To x
z = z * i
Next i
Return (z)
End Function 'PermBig
Function FactBig(x As Long) As BigInteger
Dim i As Long, z As BigInteger
z = 1
For i = 2 To x
z = z * i
Next i
Return (z)
End Function 'FactBig
Function CombBig(ByVal x As Long, ByVal y As Long) As BigInteger
If y > x Then
Return (0)
ElseIf x = y Then
Return (1)
Else
If x - y < y Then y = x - y
Return (PermBig(x, y) / FactBig(y))
End If
End Function 'CombBig
End Module |
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
| #OCaml | OCaml | (*------------------------------------------------------------------*)
(* The Rosetta Code lexical analyzer, in OCaml. Based on the ATS. *)
(* When you compare this code to the ATS code, please keep in mind
that, although ATS has an ML-like syntax:
* The type system is not the same at all.
* Most ATS functions are not closures. Those that are will have
special notations such as "<cloref1>" associated with them. *)
(*------------------------------------------------------------------*)
(* The following functions are compatible with ASCII. *)
let is_digit ichar =
48 <= ichar && ichar <= 57
let is_lower ichar =
97 <= ichar && ichar <= 122
let is_upper ichar =
65 <= ichar && ichar <= 90
let is_alpha ichar =
is_lower ichar || is_upper ichar
let is_alnum ichar =
is_digit ichar || is_alpha ichar
let is_ident_start ichar =
is_alpha ichar || ichar = 95
let is_ident_continuation ichar =
is_alnum ichar || ichar = 95
let is_space ichar =
ichar = 32 || (9 <= ichar && ichar <= 13)
(*------------------------------------------------------------------*)
let reverse_list_to_string lst =
List.rev lst |> List.to_seq |> String.of_seq
(*------------------------------------------------------------------*)
(* Character input more like that of C. There are various advantages
and disadvantages to this method, but key points in its favor are:
(a) it is how character input is done in the original ATS code, (b)
Unicode code points are 21-bit positive integers. *)
let eof = (-1)
let input_ichar channel =
try
int_of_char (input_char channel)
with
| End_of_file -> eof
(*------------------------------------------------------------------*)
(* The type of an input character. *)
module Ch =
struct
type t =
{
ichar : int;
line_no : int;
column_no : int
}
end
(*------------------------------------------------------------------*)
(* Inputting with unlimited pushback, and with counting of lines and
columns. *)
module Inp =
struct
type t =
{
inpf : in_channel;
pushback : Ch.t list;
line_no : int;
column_no : int
}
let of_in_channel inpf =
{ inpf = inpf;
pushback = [];
line_no = 1;
column_no = 1
}
let get_ch inp =
match inp.pushback with
| ch :: tail ->
(ch, {inp with pushback = tail})
| [] ->
let ichar = input_ichar inp.inpf in
if ichar = int_of_char '\n' then
({ ichar = ichar;
line_no = inp.line_no;
column_no = inp.column_no },
{ inp with line_no = inp.line_no + 1;
column_no = 1 })
else
({ ichar = ichar;
line_no = inp.line_no;
column_no = inp.column_no },
{ inp with column_no = inp.column_no + 1 })
let push_back_ch ch inp =
{inp with pushback = ch :: inp.pushback}
end
(*------------------------------------------------------------------*)
(* Tokens, appearing in tuples with arguments, and with line and
column numbers. The tokens are integers, so they can be used as
array indices. *)
(* (token, argument, line_no, column_no) *)
type toktup_t = int * string * int * int
let token_ELSE = 0
let token_IF = 1
let token_PRINT = 2
let token_PUTC = 3
let token_WHILE = 4
let token_MULTIPLY = 5
let token_DIVIDE = 6
let token_MOD = 7
let token_ADD = 8
let token_SUBTRACT = 9
let token_NEGATE = 10
let token_LESS = 11
let token_LESSEQUAL = 12
let token_GREATER = 13
let token_GREATEREQUAL = 14
let token_EQUAL = 15
let token_NOTEQUAL = 16
let token_NOT = 17
let token_ASSIGN = 18
let token_AND = 19
let token_OR = 20
let token_LEFTPAREN = 21
let token_RIGHTPAREN = 22
let token_LEFTBRACE = 23
let token_RIGHTBRACE = 24
let token_SEMICOLON = 25
let token_COMMA = 26
let token_IDENTIFIER = 27
let token_INTEGER = 28
let token_STRING = 29
let token_END_OF_INPUT = 30
;;
(* A *very* simple perfect hash for the reserved words. (Yes, this is
overkill, except for demonstration of the principle.) *)
let reserved_words =
[| "if"; "print"; "else"; ""; "putc"; ""; ""; "while"; "" |]
let reserved_word_tokens =
[| token_IF; token_PRINT; token_ELSE; token_IDENTIFIER;
token_PUTC; token_IDENTIFIER; token_IDENTIFIER; token_WHILE;
token_IDENTIFIER |]
let reserved_word_lookup s line_no column_no =
if String.length s < 2 then
(token_IDENTIFIER, s, line_no, column_no)
else
let hashval = (int_of_char s.[0] + int_of_char s.[1]) mod 9 in
let token = reserved_word_tokens.(hashval) in
if token = token_IDENTIFIER || s <> reserved_words.(hashval) then
(token_IDENTIFIER, s, line_no, column_no)
else
(token, s, line_no, column_no)
(* Token to string lookup. *)
let token_names =
[| "Keyword_else";
"Keyword_if";
"Keyword_print";
"Keyword_putc";
"Keyword_while";
"Op_multiply";
"Op_divide";
"Op_mod";
"Op_add";
"Op_subtract";
"Op_negate";
"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";
"Identifier";
"Integer";
"String";
"End_of_input" |]
let token_name token =
token_names.(token)
(*------------------------------------------------------------------*)
exception Unterminated_comment of int * int
exception Unterminated_character_literal of int * int
exception Multicharacter_literal of int * int
exception End_of_input_in_string_literal of int * int
exception End_of_line_in_string_literal of int * int
exception Unsupported_escape of int * int * int
exception Invalid_integer_literal of int * int * string
exception Unexpected_character of int * int * char
(*------------------------------------------------------------------*)
(* Skipping past spaces and comments. (A comment in the target
language is, if you think about it, a kind of space.) *)
let scan_comment inp line_no column_no =
let rec loop inp =
let (ch, inp) = Inp.get_ch inp in
if ch.ichar = eof then
raise (Unterminated_comment (line_no, column_no))
else if ch.ichar = int_of_char '*' then
let (ch1, inp) = Inp.get_ch inp in
if ch1.ichar = eof then
raise (Unterminated_comment (line_no, column_no))
else if ch1.ichar = int_of_char '/' then
inp
else
loop inp
else
loop inp
in
loop inp
let skip_spaces_and_comments inp =
let rec loop inp =
let (ch, inp) = Inp.get_ch inp in
if is_space ch.ichar then
loop inp
else if ch.ichar = int_of_char '/' then
let (ch1, inp) = Inp.get_ch inp in
if ch1.ichar = int_of_char '*' then
scan_comment inp ch.line_no ch.column_no |> loop
else
let inp = Inp.push_back_ch ch1 inp in
let inp = Inp.push_back_ch ch inp in
inp
else
Inp.push_back_ch ch inp
in
loop inp
(*------------------------------------------------------------------*)
(* Integer literals, identifiers, and reserved words. *)
(* In ATS the predicate for simple scan was supplied by template
expansion, which (typically) produces faster code than passing a
function or closure (although passing either of those could have
been done). Here I pass the predicate as a function/closure. It is
worth contrasting the methods. *)
let rec simple_scan pred lst inp =
let (ch, inp) = Inp.get_ch inp in
if pred ch.ichar then
simple_scan pred (char_of_int ch.ichar :: lst) inp
else
(lst, Inp.push_back_ch ch inp)
(* Demonstration of one way to make a new closure in OCaml. (In ATS,
one might see things that look similar but are actually template
operations.) *)
let simple_scan_iic = simple_scan is_ident_continuation
let scan_integer_literal inp =
let (ch, inp) = Inp.get_ch inp in
let _ = assert (is_digit ch.ichar) in
let (lst, inp) = simple_scan_iic [char_of_int ch.ichar] inp in
let s = reverse_list_to_string lst in
if List.for_all (fun c -> is_digit (int_of_char c)) lst then
((token_INTEGER, s, ch.line_no, ch.column_no), inp)
else
raise (Invalid_integer_literal (ch.line_no, ch.column_no, s))
let scan_identifier_or_reserved_word inp =
let (ch, inp) = Inp.get_ch inp in
let _ = assert (is_ident_start ch.ichar) in
let (lst, inp) = simple_scan_iic [char_of_int ch.ichar] inp in
let s = reverse_list_to_string lst in
let toktup = reserved_word_lookup s ch.line_no ch.column_no in
(toktup, inp)
(*------------------------------------------------------------------*)
(* String literals. *)
let scan_string_literal inp =
let (ch, inp) = Inp.get_ch inp in
let _ = assert (ch.ichar = int_of_char '"') in
let rec scan lst inp =
let (ch1, inp) = Inp.get_ch inp in
if ch1.ichar = eof then
raise (End_of_input_in_string_literal
(ch.line_no, ch.column_no))
else if ch1.ichar = int_of_char '\n' then
raise (End_of_line_in_string_literal
(ch.line_no, ch.column_no))
else if ch1.ichar = int_of_char '"' then
(lst, inp)
else if ch1.ichar <> int_of_char '\\' then
scan (char_of_int ch1.ichar :: lst) inp
else
let (ch2, inp) = Inp.get_ch inp in
if ch2.ichar = int_of_char 'n' then
scan ('n' :: '\\' :: lst) inp
else if ch2.ichar = int_of_char '\\' then
scan ('\\' :: '\\' :: lst) inp
else
raise (Unsupported_escape (ch1.line_no, ch1.column_no,
ch2.ichar))
in
let lst = '"' :: [] in
let (lst, inp) = scan lst inp in
let lst = '"' :: lst in
let s = reverse_list_to_string lst in
((token_STRING, s, ch.line_no, ch.column_no), inp)
(*------------------------------------------------------------------*)
(* Character literals. *)
let scan_character_literal_without_checking_end inp =
let (ch, inp) = Inp.get_ch inp in
let _ = assert (ch.ichar = int_of_char '\'') in
let (ch1, inp) = Inp.get_ch inp in
if ch1.ichar = eof then
raise (Unterminated_character_literal
(ch.line_no, ch.column_no))
else if ch1.ichar = int_of_char '\\' then
let (ch2, inp) = Inp.get_ch inp in
if ch2.ichar = eof then
raise (Unterminated_character_literal
(ch.line_no, ch.column_no))
else if ch2.ichar = int_of_char 'n' then
let s = (int_of_char '\n' |> string_of_int) in
((token_INTEGER, s, ch.line_no, ch.column_no), inp)
else if ch2.ichar = int_of_char '\\' then
let s = (int_of_char '\\' |> string_of_int) in
((token_INTEGER, s, ch.line_no, ch.column_no), inp)
else
raise (Unsupported_escape
(ch1.line_no, ch1.column_no, ch2.ichar))
else
let s = string_of_int ch1.ichar in
((token_INTEGER, s, ch.line_no, ch.column_no), inp)
let scan_character_literal inp =
let (toktup, inp) =
scan_character_literal_without_checking_end inp in
let (_, _, line_no, column_no) = toktup in
let check_end inp =
let (ch, inp) = Inp.get_ch inp in
if ch.ichar = int_of_char '\'' then
inp
else
let rec loop_to_end (ch1 : Ch.t) inp =
if ch1.ichar = eof then
raise (Unterminated_character_literal (line_no, column_no))
else if ch1.ichar = int_of_char '\'' then
raise (Multicharacter_literal (line_no, column_no))
else
let (ch1, inp) = Inp.get_ch inp in
loop_to_end ch1 inp
in
loop_to_end ch inp
in
let inp = check_end inp in
(toktup, inp)
(*------------------------------------------------------------------*)
let get_next_token inp =
let inp = skip_spaces_and_comments inp in
let (ch, inp) = Inp.get_ch inp in
let ln = ch.line_no in
let cn = ch.column_no in
if ch.ichar = eof then
((token_END_OF_INPUT, "", ln, cn), inp)
else
match char_of_int ch.ichar with
| ',' -> ((token_COMMA, ",", ln, cn), inp)
| ';' -> ((token_SEMICOLON, ";", ln, cn), inp)
| '(' -> ((token_LEFTPAREN, "(", ln, cn), inp)
| ')' -> ((token_RIGHTPAREN, ")", ln, cn), inp)
| '{' -> ((token_LEFTBRACE, "{", ln, cn), inp)
| '}' -> ((token_RIGHTBRACE, "}", ln, cn), inp)
| '*' -> ((token_MULTIPLY, "*", ln, cn), inp)
| '/' -> ((token_DIVIDE, "/", ln, cn), inp)
| '%' -> ((token_MOD, "%", ln, cn), inp)
| '+' -> ((token_ADD, "+", ln, cn), inp)
| '-' -> ((token_SUBTRACT, "-", ln, cn), inp)
| '<' ->
let (ch1, inp) = Inp.get_ch inp in
if ch1.ichar = int_of_char '=' then
((token_LESSEQUAL, "<=", ln, cn), inp)
else
let inp = Inp.push_back_ch ch1 inp in
((token_LESS, "<", ln, cn), inp)
| '>' ->
let (ch1, inp) = Inp.get_ch inp in
if ch1.ichar = int_of_char '=' then
((token_GREATEREQUAL, ">=", ln, cn), inp)
else
let inp = Inp.push_back_ch ch1 inp in
((token_GREATER, ">", ln, cn), inp)
| '=' ->
let (ch1, inp) = Inp.get_ch inp in
if ch1.ichar = int_of_char '=' then
((token_EQUAL, "==", ln, cn), inp)
else
let inp = Inp.push_back_ch ch1 inp in
((token_ASSIGN, "=", ln, cn), inp)
| '!' ->
let (ch1, inp) = Inp.get_ch inp in
if ch1.ichar = int_of_char '=' then
((token_NOTEQUAL, "!=", ln, cn), inp)
else
let inp = Inp.push_back_ch ch1 inp in
((token_NOT, "!", ln, cn), inp)
| '&' ->
let (ch1, inp) = Inp.get_ch inp in
if ch1.ichar = int_of_char '&' then
((token_AND, "&&", ln, cn), inp)
else
raise (Unexpected_character (ch.line_no, ch.column_no,
char_of_int ch.ichar))
| '|' ->
let (ch1, inp) = Inp.get_ch inp in
if ch1.ichar = int_of_char '|' then
((token_OR, "||", ln, cn), inp)
else
raise (Unexpected_character (ch.line_no, ch.column_no,
char_of_int ch.ichar))
| '"' ->
let inp = Inp.push_back_ch ch inp in
scan_string_literal inp
| '\'' ->
let inp = Inp.push_back_ch ch inp in
scan_character_literal inp
| _ when is_digit ch.ichar ->
let inp = Inp.push_back_ch ch inp in
scan_integer_literal inp
| _ when is_ident_start ch.ichar ->
let inp = Inp.push_back_ch ch inp in
scan_identifier_or_reserved_word inp
| _ -> raise (Unexpected_character (ch.line_no, ch.column_no,
char_of_int ch.ichar))
let print_token outf toktup =
let (token, arg, line_no, column_no) = toktup in
let name = token_name token in
let (padding, str) =
match 0 with
| _ when token = token_IDENTIFIER -> (" ", arg)
| _ when token = token_INTEGER -> (" ", arg)
| _ when token = token_STRING -> (" ", arg)
| _ -> ("", "")
in
Printf.fprintf outf "%5d %5d %s%s%s\n"
line_no column_no name padding str
let scan_text outf inp =
let rec loop inp =
let (toktup, inp) = get_next_token inp in
begin
print_token outf toktup;
let (token, _, _, _) = toktup in
if token <> token_END_OF_INPUT then
loop inp
end
in
loop inp
(*------------------------------------------------------------------*)
let main () =
let inpf_filename =
if 2 <= Array.length Sys.argv then
Sys.argv.(1)
else
"-"
in
let outf_filename =
if 3 <= Array.length Sys.argv then
Sys.argv.(2)
else
"-"
in
let inpf =
if inpf_filename = "-" then
stdin
else
open_in inpf_filename
in
let outf =
if outf_filename = "-" then
stdout
else
open_out outf_filename
in
let inp = Inp.of_in_channel inpf in
scan_text outf inp
;;
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"
| #LFE | LFE |
$ ./bin/lfe -pa ebin/ -c "alpha beta" -h "gamma"
|
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"
| #Liberty_BASIC | Liberty BASIC | print CommandLine$ |
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"
| #Lingo | Lingo | put the commandline
-- "-c alpha beta -h gamma" |
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.)
| #Dylan | Dylan | // This is a comment
/*
This is a comment
that spans 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.)
| #D.C3.A9j.C3.A0_Vu | Déjà Vu | #this is a comment
!print "this is not a comment, obviously" #this is a comment as well |
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.
| #JAMES_II.2FRule-based_Cellular_Automata | JAMES II/Rule-based Cellular Automata | @caversion 1;
dimensions 2;
//using Moore neighborhood
neighborhood moore;
//available states
state DEAD, ALIVE;
/*
if current state is ALIVE and the
neighborhood does not contain 2 or
3 ALIVE states the cell changes to
DEAD
*/
rule{ALIVE}:!ALIVE{2,3}->DEAD;
/*
if current state is DEAD and there
are exactly 3 ALIVE cells in the
neighborhood the cell changes to
ALIVE
*/
rule{DEAD}:ALIVE{3}->ALIVE; |
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.
| #D | D | void main() {
enum int i = 5;
// "static if" for various static checks:
static if (i == 7) {
// ...
} else {
//...
}
// is(T == U) checks if type T is U.
static if (is(typeof(i) == int)) {
// ...
} else {
// ...
}
// D switch is improved over C switch:
switch (i) {
case 0:
break; // Silent fallthrough is forbidden.
case 1:
goto case; // Explicit fallthrough.
case 2:
// Empty cases don't require an explicit fallthrough.
case 3:
return;
case 4, 5, 7: // Multiple cases.
break;
case 8: .. case 15: // Inclusive interval.
goto case 3;
default: // Default case is required.
break;
}
enum Colors { yellow, blue, brown, green }
immutable c = Colors.blue;
// "final switch" is safer, for enums (and in future other values,
// like Algebraic), because all cases must be present.
// with() is handy to avoid repeating "Colors." for each case.
final switch (c) with (Colors) {
case yellow: break;
case blue: break;
case brown, green: break;
// case yellow: .. case brown: // Forbidden in final switches.
// default: // Forbidden in final switches.
}
} |
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
| #Plain_English | Plain English | To decide if some string things are lexically equal:
If the string things are empty, say yes.
Get a string thing from the string things.
Put the string thing's string into a canonical string.
Loop.
If the string thing is nil, say yes.
If the string thing's string is not the canonical string, say no.
Put the string thing's next into the string thing.
Repeat.
To decide if some string things are in ascending order:
If the string things' count is less than 2, say yes.
Get a string thing from the string things.
Put the string thing's next into the string thing.
Loop.
If the string thing is nil, say yes.
If the string thing's string is less than the string thing's previous' string, say no.
Put the string thing's next into the string thing.
Repeat. |
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
| #PowerShell | PowerShell |
function IsAscending ( [string[]]$Array ) { ( 0..( $Array.Count - 2 ) ).Where{ $Array[$_] -le $Array[$_+1] }.Count -eq $Array.Count - 1 }
function IsEqual ( [string[]]$Array ) { ( 0..( $Array.Count - 2 ) ).Where{ $Array[$_] -eq $Array[$_+1] }.Count -eq $Array.Count - 1 }
IsAscending 'A', 'B', 'B', 'C'
IsAscending 'A', 'C', 'B', 'C'
IsAscending 'A', 'A', 'A', 'A'
IsEqual 'A', 'B', 'B', 'C'
IsEqual 'A', 'C', 'B', 'C'
IsEqual 'A', 'A', 'A', 'A'
|
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.
| #Icon_and_Unicon | Icon and Unicon | procedure main()
every write(quibble([] | ["ABC"] | ["ABC","DEF"] | ["ABC","DEF","G","H"]))
end
procedure quibble(A)
join := s := ""
while s := pull(A)||join||s do join := if *join = 0 then " and " else ", "
return "{"||s||"}"
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.
| #J | J | quibLast2=: ' and ' joinstring (2 -@<. #) {. ]
withoutLast2=: ([: # _2&}.) {. ]
quibble=: '{', '}' ,~ ', ' joinstring withoutLast2 , <@quibLast2 |
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
| #Perl | Perl | sub p { $_[0] ? map p($_[0] - 1, [@{$_[1]}, $_[$_]], @_[$_ .. $#_]), 2 .. $#_ : $_[1] }
sub f { $_[0] ? $_[0] * f($_[0] - 1) : 1 }
sub pn{ f($_[0] + $_[1] - 1) / f($_[0]) / f($_[1] - 1) }
for (p(2, [], qw(iced jam plain))) {
print "@$_\n";
}
printf "\nThere are %d ways to pick 7 out of 10\n", pn(7,10);
|
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
| #Wren | Wren | import "/big" for BigInt
import "/fmt" for Fmt
import "/trait" for Stepped
var perm = Fn.new { |n, k|
if (n <= 0 || k < 0) Fiber.abort("Invalid argument(s).")
if (k == 0) return BigInt.one
return (n-k+1..n).reduce(BigInt.one) { |acc, i| acc * BigInt.new(i) }
}
var comb = Fn.new { |n, k|
if (n <= 0 || k < 0) Fiber.abort("Invalid argument(s).")
var fact = BigInt.one
if (k > 1) fact = (2..k).reduce(BigInt.one) { |acc, i| acc * BigInt.new(i) }
return perm.call(n, k) / fact
}
System.print("A sample of permutations from 1 to 12:")
for (n in 1..12) Fmt.print("$2d P $-2d = $i", n, (n/3).floor, perm.call(n, (n/3).floor))
System.print("\nA sample of combinations from 10 to 60:")
for (n in Stepped.new(10..60, 10)) {
Fmt.print("$2d C $-2d = $i", n, (n/3).floor, comb.call(n, (n/3).floor))
}
System.print("\nA sample of permutations from 5 to 15000:")
var na = [5, 50, 500, 1000, 5000, 15000]
for (n in na) {
var k = (n/3).floor
var s = perm.call(n, k).toString
var l = s.count
var e = (l <= 40) ? "" : "... (%(l - 40) more digits)"
Fmt.print("$5d P $-4d = $s$s", n, k, s.take(40).join(), e)
}
System.print("\nA sample of combinations from 100 to 1000:")
for (n in Stepped.new(100..1000, 100)) {
var k = (n/3).floor
var s = comb.call(n, k).toString
var l = s.count
var e = (l <= 40) ? "" : "... (%(l - 40) more digits)"
Fmt.print("$4d C $-3d = $s$s", n, k, s.take(40).join(), e)
} |
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
| #Ol | Ol |
(import (owl parse))
(define (get-comment)
(get-either
(let-parses (
(_ (get-imm #\*))
(_ (get-imm #\/)))
#true)
(let-parses (
(_ get-byte)
(_ (get-comment)))
#true)))
(define get-whitespace
(get-any-of
(get-byte-if (lambda (x) (has? '(#\tab #\newline #\space #\return) x))) ; whitespace
(let-parses ( ; comment
(_ (get-imm #\/))
(_ (get-imm #\*))
(_ (get-comment)))
#true)))
(define get-operator
(let-parses (
(operator (get-any-of
(get-word "||" 'Op_or)
(get-word "&&" 'Op_and)
(get-word "!=" 'Op_notequal)
(get-word "==" 'Op_equal)
(get-word ">=" 'Op_greaterequal)
(get-word "<=" 'Op_lessequal)
(get-word "=" 'Op_assign)
(get-word "!" 'Op_nop)
(get-word ">" 'Op_greater)
(get-word "<" 'Op_less)
(get-word "-" 'Op_subtract)
(get-word "+" 'Op_add)
(get-word "%" 'Op_mod)
(get-word "/" 'Op_divide)
(get-word "*" 'Op_multiply))))
(cons 'operator operator)))
(define get-symbol
(let-parses (
(symbol (get-any-of
(get-word "(" 'LeftParen)
(get-word ")" 'RightParen)
(get-word "{" 'LeftBrace)
(get-word "}" 'RightBrace)
(get-word ";" 'Semicolon)
(get-word "," 'Comma))))
(cons 'symbol symbol)))
(define get-keyword
(let-parses (
(keyword (get-any-of
(get-word "if" 'Keyword_if)
(get-word "else" 'Keyword_else)
(get-word "while" 'Keyword_while)
(get-word "print" 'Keyword_print)
(get-word "putc" 'Keyword_putc))))
(cons 'keyword keyword)))
(define get-identifier
(let-parses (
(lead (get-byte-if (lambda (x) (or (<= #\a x #\z) (<= #\A x #\Z) (= x #\_)))))
(tail (get-greedy* (get-byte-if (lambda (x) (or (<= #\a x #\z) (<= #\A x #\Z) (= x #\_) (<= #\0 x #\9)))))))
(cons 'identifier (bytes->string (cons lead tail)))))
(define get-integer
(let-parses (
(main (get-greedy+ (get-byte-if (lambda (x) (<= #\0 x #\9))))) )
(cons 'integer (string->integer (bytes->string main)))))
(define get-character
(let-parses (
(_ (get-imm #\'))
(char (get-any-of
(get-word "\\n" #\newline)
(get-word "\\\\" #\\)
(get-byte-if (lambda (x) (not (or (eq? x #\') (eq? x #\newline)))))))
(_ (get-imm #\')) )
(cons 'character char)))
(define get-string
(let-parses (
(_ (get-imm #\")) ;"
(data (get-greedy* (get-any-of
(get-word "\\n" #\newline)
(get-word "\\\\" #\\) ;\"
(get-byte-if (lambda (x) (not (or (eq? x #\") (eq? x #\newline)))))))) ;", newline
(_ (get-imm #\")) ) ;"
(cons 'string (bytes->string data))))
(define get-token
(let-parses (
(_ (get-greedy* get-whitespace))
(token (get-any-of
get-symbol
get-keyword
get-identifier
get-operator
get-integer
get-character
get-string
)) )
token))
(define token-parser
(let-parses (
(tokens (get-greedy+ get-token))
(_ (get-greedy* get-whitespace)))
tokens))
(define (translate source)
(let ((stream (try-parse token-parser (str-iter source) #t)))
(for-each print (car stream))
(if (null? (cdr stream))
(print 'End_of_input))))
|
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"
| #Logo | Logo | logo file.logo - arg1 arg2 arg3
|
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.)
| #E | E | # This is a regular comment.
? "This is an Updoc comment, which
> is an executable example or test case.".split(" ")
# value: ["This", "is", "an", "Updoc", "comment,", "which
# is", "an", "executable", "example", "or", "test", "case."] |
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.)
| #EasyLang | EasyLang | # This is 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.
| #Java | Java | public class GameOfLife{
public static void main(String[] args){
String[] dish= {
"_#_",
"_#_",
"_#_",};
int gens= 3;
for(int i= 0;i < gens;i++){
System.out.println("Generation " + i + ":");
print(dish);
dish= life(dish);
}
}
public static String[] life(String[] dish){
String[] newGen= new String[dish.length];
for(int row= 0;row < dish.length;row++){//each row
newGen[row]= "";
for(int i= 0;i < dish[row].length();i++){//each char in the row
String above= "";//neighbors above
String same= "";//neighbors in the same row
String below= "";//neighbors below
if(i == 0){//all the way on the left
//no one above if on the top row
//otherwise grab the neighbors from above
above= (row == 0) ? null : dish[row - 1].substring(i,
i + 2);
same= dish[row].substring(i + 1, i + 2);
//no one below if on the bottom row
//otherwise grab the neighbors from below
below= (row == dish.length - 1) ? null : dish[row + 1]
.substring(i, i + 2);
}else if(i == dish[row].length() - 1){//right
//no one above if on the top row
//otherwise grab the neighbors from above
above= (row == 0) ? null : dish[row - 1].substring(i - 1,
i + 1);
same= dish[row].substring(i - 1, i);
//no one below if on the bottom row
//otherwise grab the neighbors from below
below= (row == dish.length - 1) ? null : dish[row + 1]
.substring(i - 1, i + 1);
}else{//anywhere else
//no one above if on the top row
//otherwise grab the neighbors from above
above= (row == 0) ? null : dish[row - 1].substring(i - 1,
i + 2);
same= dish[row].substring(i - 1, i)
+ dish[row].substring(i + 1, i + 2);
//no one below if on the bottom row
//otherwise grab the neighbors from below
below= (row == dish.length - 1) ? null : dish[row + 1]
.substring(i - 1, i + 2);
}
int neighbors= getNeighbors(above, same, below);
if(neighbors < 2 || neighbors > 3){
newGen[row]+= "_";//<2 or >3 neighbors -> die
}else if(neighbors == 3){
newGen[row]+= "#";//3 neighbors -> spawn/live
}else{
newGen[row]+= dish[row].charAt(i);//2 neighbors -> stay
}
}
}
return newGen;
}
public static int getNeighbors(String above, String same, String below){
int ans= 0;
if(above != null){//no one above
for(char x: above.toCharArray()){//each neighbor from above
if(x == '#') ans++;//count it if someone is here
}
}
for(char x: same.toCharArray()){//two on either side
if(x == '#') ans++;//count it if someone is here
}
if(below != null){//no one below
for(char x: below.toCharArray()){//each neighbor below
if(x == '#') ans++;//count it if someone is here
}
}
return ans;
}
public static void print(String[] dish){
for(String s: dish){
System.out.println(s);
}
}
} |
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.
| #Dao | Dao | a = 3
if( a == 1 ){
io.writeln( 'a == 1' )
}else if( a== 3 ){
io.writeln( 'a == 3' )
}else{
io.writeln( 'a is neither 1 nor 3' )
} |
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
| #Prolog | Prolog | los(["AA","BB","CC"]).
los(["AA","AA","AA"]).
los(["AA","CC","BB"]).
los(["AA","ACB","BB","CC"]).
los(["single_element"]).
lexically_equal(S,S,S).
in_order(G,L,G) :- compare(<,L,G).
test_list(List) :-
List = [L|T],
write('for list '), write(List), nl,
(foldl(lexically_equal, T, L, _)
-> writeln('The items in the list ARE lexically equal')
; writeln('The items in the list are NOT lexically equal')),
(foldl(in_order, T, L, _)
-> writeln('The items in the list ARE in ascending order')
; writeln('The items in the list are NOT in ascending order')),
nl.
test :- forall(los(List), test_list(List)). |
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.
| #Java | Java | public class Quibbler {
public static String quibble(String[] words) {
String qText = "{";
for(int wIndex = 0; wIndex < words.length; wIndex++) {
qText += words[wIndex] + (wIndex == words.length-1 ? "" :
wIndex == words.length-2 ? " and " :
", ";
}
qText += "}";
return qText;
}
public static void main(String[] args) {
System.out.println(quibble(new String[]{}));
System.out.println(quibble(new String[]{"ABC"}));
System.out.println(quibble(new String[]{"ABC", "DEF"}));
System.out.println(quibble(new String[]{"ABC", "DEF", "G"}));
System.out.println(quibble(new String[]{"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
| #Phix | Phix | with javascript_semantics
procedure show_choices(sequence set, integer n, at=1, sequence res={})
if length(res)=n then
?res
else
for i=at to length(set) do
show_choices(set,n,i,append(deep_copy(res),set[i]))
end for
end if
end procedure
show_choices({"iced","jam","plain"},2)
|
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
| #PHP | PHP | <?php
function combos($arr, $k) {
if ($k == 0) {
return array(array());
}
if (count($arr) == 0) {
return array();
}
$head = $arr[0];
$combos = array();
$subcombos = combos($arr, $k-1);
foreach ($subcombos as $subcombo) {
array_unshift($subcombo, $head);
$combos[] = $subcombo;
}
array_shift($arr);
$combos = array_merge($combos, combos($arr, $k));
return $combos;
}
$arr = array("iced", "jam", "plain");
$result = combos($arr, 2);
foreach($result as $combo) {
echo implode(' ', $combo), "<br>";
}
$donuts = range(1, 10);
$num_donut_combos = count(combos($donuts, 3));
echo "$num_donut_combos ways to order 3 donuts given 10 types";
?> |
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
| #Perl | Perl | #!/usr/bin/env perl
use strict;
use warnings;
no warnings 'once';
#----- Definition of the language to be lexed -----#
my @tokens = (
# Name | Format | Value #
# -------------- |----------------------|-------------#
['Op_multiply' , '*' , ],
['Op_divide' , '/' , ],
['Op_mod' , '%' , ],
['Op_add' , '+' , ],
['Op_subtract' , '-' , ],
['Op_lessequal' , '<=' , ],
['Op_less' , '<' , ],
['Op_greaterequal', '>=' , ],
['Op_greater' , '>' , ],
['Op_equal' , '==' , ],
['Op_assign' , '=' , ],
['Op_not' , '!' , ],
['Op_notequal' , '!=' , ],
['Op_and' , '&&' , ],
['Op_or' , '||' , ],
['Keyword_else' , qr/else\b/ , ],
['Keyword_if' , qr/if\b/ , ],
['Keyword_while' , qr/while\b/ , ],
['Keyword_print' , qr/print\b/ , ],
['Keyword_putc' , qr/putc\b/ , ],
['LeftParen' , '(' , ],
['RightParen' , ')' , ],
['LeftBrace' , '{' , ],
['RightBrace' , '}' , ],
['Semicolon' , ';' , ],
['Comma' , ',' , ],
['Identifier' , qr/[_a-z][_a-z0-9]*/i, \&raw ],
['Integer' , qr/[0-9]+\b/ , \&raw ],
['Integer' , qr/'([^']*)(')?/ , \&char_val ],
['String' , qr/"([^"]*)(")?/ , \&string_raw],
['End_of_input' , qr/$/ , ],
);
my $comment = qr/\/\* .+? (?: \*\/ | $ (?{die "End-of-file in comment\n"}) )/xs;
my $whitespace = qr/(?: \s | $comment)*/x;
my $unrecognized = qr/\w+ | ./x;
#| Returns the value of a matched char literal, or dies if it is invalid
sub char_val {
my $str = string_val();
die "Multiple characters\n" if length $str > 1;
die "No character\n" if length $str == 0;
ord $str;
}
#| Returns the value of a matched string literal, or dies if it is invalid
sub string_val {
my ($str, $end) = ($1, $2);
die "End-of-file\n" if not defined $end;
die "End-of-line\n" if $str =~ /\n/;
$str =~ s/\\(.)/
$1 eq 'n' ? "\n"
: $1 eq '\\' ? $1
: $1 eq $end ? $1
: die "Unknown escape sequence \\$1\n"
/rge;
}
#| Returns the source string of a matched literal
sub raw { $& }
#| Returns the source string of a matched string literal, or dies if invalid
sub string_raw {
string_val(); # Just for the error handling side-effects
$&;
}
#----- Lexer "engine" -----#
# Construct the scanner regex:
my $tokens =
join "|",
map {
my $format = $tokens[$_][1];
"\n".(ref $format ? $format : quotemeta $format)." (*MARK:$_) ";
} 0..$#tokens;
my $regex = qr/
\G (?| $whitespace \K (?| $tokens )
| $whitespace? \K ($unrecognized) (*MARK:!) )
/x;
# Run the lexer:
my $input = do { local $/ = undef; <STDIN> };
my $pos = 0;
my $linecol = linecol_accumulator();
while ($input =~ /$regex/g) {
# Get the line and column number
my ($line, $col) = $linecol->(substr $input, $pos, $-[0] - $pos);
$pos = $-[0];
# Get the token type that was identified by the scanner regex
my $type = $main::REGMARK;
die "Unrecognized token $1 at line $line, col $col\n" if $type eq '!';
my ($name, $evaluator) = @{$tokens[$type]}[0, 2];
# Get the token value
my $value;
if ($evaluator) {
eval { $value = $evaluator->() };
if ($@) { chomp $@; die "$@ in $name at line $line, col $col\n" }
}
# Print the output line
print "$line\t$col\t$name".($value ? "\t$value" : '')."\n";
}
#| Returns a closure, which can be fed a string one piece at a time and gives
#| back the cumulative line and column number each time
sub linecol_accumulator {
my ($line, $col) = (1, 1);
sub {
my $str = shift;
my @lines = split "\n", $str, -1;
my ($l, $c) = @lines ? (@lines - 1, length $lines[-1]) : (0, 0);
if ($l) { $line += $l; $col = 1 + $c }
else { $col += $c }
($line, $col)
}
} |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #LSE64 | LSE64 | argc , nl # number of arguments (including command itself)
0 # argument
dup arg dup 0 = || ,t 1 + repeat
drop |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Lua | Lua | print( "Program name:", arg[0] )
print "Arguments:"
for i = 1, #arg do
print( i," ", arg[i] )
end |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #M2000_Interpreter | M2000 Interpreter |
Module Checkit {
Document a$ = {
Module Global A {
Show
Read a$="nothing", x=0
Print a$, x
A$=Key$
}
A: End
}
Dir temporary$
Save.doc a$, "program.gsb"
\\ open if gsb extension is register to m2000.exe
Win quote$(dir$+"program.gsb")
\\ +txt is a switch for interpreter to use string comparison as text (not binary)
\\ so we can send switches and commands before the program loading
Win appdir$+"m2000.exe", quote$(dir$+"program.gsb +txt : Data {Hello}, 100")
\\ no coma after name (we can use "program.gsb" for names with spaces)
Use program.gsb "From Use statement", 200
\\ delete file
Wait 5000
Dos "del "+quote$(dir$+"program.gsb");
\\ open directory
Rem : Win temporary$
}
Checkit
|
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.)
| #EchoLisp | EchoLisp |
666 ; this is an end-of-line comment
#|
This is a multi-line comment
Nesting is not allowed
|#
;; The (info <name> [<string>)] function associates a symbol and a comment
;; These info strings are saved in permanent memory (local storage)
;; Unicode characters may be used, as everywhere in the language
(define mynumber 666) → mynumber
(info 'mynumber "👀 Symbols may be commented with an information string 👺")
(info 'mynumber) → displays the above inside the 'info' field.
|
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.)
| #ECL | ECL | // this is a one-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.
| #JavaScript | JavaScript | function GameOfLife () {
this.init = function (turns,width,height) {
this.board = new Array(height);
for (var x = 0; x < height; x++) {
this.board[x] = new Array(width);
for (var y = 0; y < width; y++) {
this.board[x][y] = Math.round(Math.random());
}
}
this.turns = turns;
}
this.nextGen = function() {
this.boardNext = new Array(this.board.length);
for (var i = 0; i < this.board.length; i++) {
this.boardNext[i] = new Array(this.board[i].length);
}
for (var x = 0; x < this.board.length; x++) {
for (var y = 0; y < this.board[x].length; y++) {
var n = 0;
for (var dx = -1; dx <= 1; dx++) {
for (var dy = -1; dy <= 1; dy++) {
if ( dx == 0 && dy == 0){}
else if (typeof this.board[x+dx] !== 'undefined'
&& typeof this.board[x+dx][y+dy] !== 'undefined'
&& this.board[x+dx][y+dy]) {
n++;
}
}
}
var c = this.board[x][y];
switch (n) {
case 0:
case 1:
c = 0;
break;
case 2:
break;
case 3:
c = 1;
break;
default:
c = 0;
}
this.boardNext[x][y] = c;
}
}
this.board = this.boardNext.slice();
}
this.print = function() {
for (var x = 0; x < this.board.length; x++) {
var l = "";
for (var y = 0; y < this.board[x].length; y++) {
if (this.board[x][y])
l += "X";
else
l += " ";
}
print(l);
}
}
this.start = function() {
for (var t = 0; t < this.turns; t++) {
print("---\nTurn "+(t+1));
this.print();
this.nextGen()
}
}
}
var game = new GameOfLife();
print("---\n3x3 Blinker over three turns.");
game.init(3);
game.board = [
[0,0,0],
[1,1,1],
[0,0,0]];
game.start();
print("---\n10x6 Glider over five turns.");
game.init(5);
game.board = [
[0,0,0,0,0,0,0,0,0,0],
[0,0,1,0,0,0,0,0,0,0],
[0,0,0,1,0,0,0,0,0,0],
[0,1,1,1,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0]];
game.start();
print("---\nRandom 5x10");
game.init(5,5,10);
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.
| #Delphi | Delphi | if (input.Field == "Hello World") {
sVar = "good";
} else if (input.Field == "Bye World") {
sVar = "bad";
} else {
sVar = "neutral";
} |
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
| #PureBasic | PureBasic | EnableExplicit
DataSection
Data.s ~"AA\tAA\tAA\nAA\tBB\tCC\nAA\tCC\tBB\nAA\tACB\tBB\tCC\nsingel_element"
EndDataSection
Macro PassFail(PF)
If PF : PrintN("Pass") : Else : PrintN("Fail") : EndIf
EndMacro
Macro ProcRec(Proc)
Define tf1$,tf2$ : Static chk.b : chk=#True
tf1$=StringField(s$,c,tz$) : tf2$=StringField(s$,c+1,tz$)
If Len(tf2$) : Proc(s$,tz$,c+1) : EndIf
EndMacro
Procedure.b IsStringsEqual(s$,tz$=~"\t",c.i=1)
ProcRec(IsStringsEqual)
chk & Bool(tf1$=tf2$ Or tf2$="")
ProcedureReturn chk
EndProcedure
Procedure.b IsStringsAscending(s$,tz$=~"\t",c.i=1)
ProcRec(IsStringsAscending)
chk & Bool(tf1$<tf2$ Or tf2$="")
ProcedureReturn chk
EndProcedure
Define t$,sf$,c.i,i.i,PF.b
Read.s t$ : c=CountString(t$,~"\n")
OpenConsole("Compare a list of Strings")
For i=1 To c+1
sf$=StringField(t$,i,~"\n")
PrintN("List : "+sf$)
Print("Lexical test : ") : PassFail(IsStringsEqual(sf$))
Print("Ascending test : ") : PassFail(IsStringsAscending(sf$))
PrintN("")
Next
Input() |
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.
| #JavaScript | JavaScript | function quibble(words) {
return "{" +
words.slice(0, words.length-1).join(",") +
(words.length > 1 ? " and " : "") +
(words[words.length-1] || '') +
"}";
}
[[], ["ABC"], ["ABC", "DEF"], ["ABC", "DEF", "G", "H"]].forEach(
function(s) {
console.log(quibble(s));
}
); |
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
| #PicoLisp | PicoLisp | (de combrep (N Lst)
(cond
((=0 N) '(NIL))
((not Lst))
(T
(conc
(mapcar
'((X) (cons (car Lst) X))
(combrep (dec N) Lst) )
(combrep N (cdr Lst)) ) ) ) ) |
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
| #Prolog | Prolog |
combinations_of_length(_,[]).
combinations_of_length([X|T],[X|Combinations]):-
combinations_of_length([X|T],Combinations).
combinations_of_length([_|T],[X|Combinations]):-
combinations_of_length(T,[X|Combinations]).
|
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
| #Phix | Phix | --
-- demo\rosetta\Compiler\core.e
-- ============================
--
-- Standard declarations and routines used by lex.exw, parse.exw, cgen.exw, and interp.exw
-- (included in distribution as above, which contains some additional sanity checks)
--
with javascript_semantics
global constant EOF = -1, STDIN = 0, STDOUT = 1
global enum NONE=0, UNARY=1, BINARY=2
global type nary(integer n) return n=NONE or n=UNARY or n=BINARY end type
global sequence tkNames = {} -- eg/ie {"Op_multiply","Op_divide",..}
global sequence precedences = {}
global sequence narys = {} -- NONE/UNARY/BINARY
global sequence operators = {} -- eg/ie {"*","/","+","-","<","<=",..}
global sequence opcodes = {} -- idx to tkNames, matching operators
global constant KEYWORDS = new_dict() -- eg/ie {"if"=>idx to tkNames}
global enum OPERATOR=1, DIGIT, LETTER -- character classes
global sequence charmap = repeat(0,255)
charmap['0'..'9'] = DIGIT
charmap['A'..'Z'] = LETTER
charmap['a'..'z'] = LETTER
charmap['_'] = LETTER
function tkName(string s, nary n = NONE, integer precedence = -1)
tkNames = append(tkNames,s)
narys = append(narys,n)
precedences = append(precedences,precedence)
return length(tkNames)
end function
function tkOp(string s, string op, nary n, integer precedence)
integer res = tkName(s, n, precedence)
operators = append(operators,op)
opcodes = append(opcodes,res)
for i=1 to length(op) do
charmap[op[i]] = OPERATOR
end for
return res
end function
function tkKw(string s, string keyword)
integer res = tkName(s)
putd(keyword, res, KEYWORDS)
return res
end function
global constant
tk_EOI = tkName("End_of_input"), --1
tk_mul = tkOp("Op_multiply", "*", BINARY,13), --2
tk_div = tkOp("Op_divide", "/", BINARY,13), --3
tk_mod = tkOp("Op_mod", "%", BINARY,13), --4
tk_add = tkOp("Op_add", "+", BINARY,12), --5
tk_sub = tkOp("Op_subtract", "-", BINARY,12), --6
tk_neg = tkName("Op_negate", UNARY, 14), --7
tk_not = tkOp("Op_not", "!", UNARY, 14), --8
tk_lt = tkOp("Op_less", "<", BINARY,10), --9
tk_le = tkOp("Op_lessequal", "<=",BINARY,10), --10
tk_gt = tkOp("Op_greater", ">", BINARY,10), --11
tk_ge = tkOp("Op_greaterequal", ">=",BINARY,10), --12
tk_eq = tkOp("Op_equal", "==",BINARY, 9), --13
tk_ne = tkOp("Op_notequal", "!=",BINARY, 9), --14
tk_assign = tkOp("Op_assign", "=", NONE, -1), --15
tk_and = tkOp("Op_and", "&&",BINARY, 5), --16
tk_or = tkOp("Op_or", "||",BINARY, 4), --17
tk_if = tkKw("Keyword_if", "if"), --18
tk_else = tkKw("Keyword_else", "else"), --19
tk_while = tkKw("Keyword_while","while"), --20
tk_print = tkKw("Keyword_print","print"), --21
tk_putc = tkKw("Keyword_putc", "putc"), --22
tk_LeftParen = tkOp("LeftParen", "(", NONE, -1), --23
tk_RightParen = tkOp("RightParen", ")", NONE, -1), --24
tk_LeftBrace = tkOp("LeftBrace", "{", NONE, -1), --25
tk_RightBrace = tkOp("RightBrace", "}", NONE, -1), --26
tk_Semicolon = tkOp("Semicolon", ";", NONE, -1), --27
tk_Comma = tkOp("Comma", ",", NONE, -1), --28
tk_Identifier = tkName("Identifier"), --29
tk_Integer = tkName("Integer"), --30
tk_String = tkName("String"), --31
tk_Sequence = tkName("Sequence"), --32
tk_Prints = tkName("tk_Prints"), --33
tk_Printi = tkName("tk_Printi") --34
global integer input_file = STDIN,
output_file = STDOUT
type strint(object o)
return string(o) or integer(o)
end type
global strint tok_line, -- save of line/col at the start of
tok_col -- token/comment, for result/errors
global object oneline = ""
constant errfmt = "Line %s column %s:\n%s%s"
function errline()
oneline = substitute(trim(oneline,"\r\n"),'\t',' ')
string padding = repeat(' ',tok_col)
return sprintf("%s\n%s^ ",{oneline,padding})
end function
global procedure error(sequence msg, sequence args={})
if length(args) then
msg = sprintf(msg,args)
end if
string el = iff(atom(oneline)?"":errline())
if integer(tok_line) then tok_line = sprintf("%d",tok_line) end if
if integer(tok_col) then tok_col = sprintf("%d",tok_col) end if
printf(STDOUT,errfmt,{tok_line,tok_col,el,msg})
{} = wait_key()
abort(1)
end procedure
include js_io.e -- fake file i/o for running under pwa/p2js
function open_file(string file_name, string mode)
integer fn = iff(platform()=JS?js_open(file_name)
:open(file_name, mode))
if fn<=0 then
printf(STDOUT, "Could not open %s", {file_name})
{} = wait_key()
abort(1)
end if
return fn
end function
global procedure open_files(sequence cl)
if length(cl)>2 then
input_file = open_file(cl[3],"r")
if length(cl)>3 then
output_file = open_file(cl[4],"w")
end if
end if
end procedure
global procedure close_files()
if platform()!=JS then
if input_file!=STDIN then close(input_file) end if
if output_file!=STDOUT then close(output_file) end if
end if
end procedure
global function enquote(string s)
return sprintf(`"%s"`,substitute(s,"\n","\\n"))
end function
global function unquote(string s)
if s[1]!='\"' then ?9/0 end if
if s[$]!='\"' then ?9/0 end if
s = substitute(s[2..-2],"\\n","\n")
return s
end function
|
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"
| #Mathematica.2FWolfram_Language | Mathematica/Wolfram Language | #!/usr/local/bin/MathematicaScript -script
$CommandLine |
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"
| #Mercury | Mercury |
:- module cmd_line_args.
:- interface.
:- import_module io.
:- pred main(io::di, io::uo) is det.
:- implementation.
:- import_module int, list, string.
main(!IO) :-
io.progname("", ProgName, !IO),
io.format("This program is named %s.\n", [s(ProgName)], !IO),
io.command_line_arguments(Args, !IO),
list.foldl2(print_arg, Args, 1, _, !IO).
:- pred print_arg(string::in, int::in, int::out, io::di, io::uo) is det.
print_arg(Arg, ArgNum, ArgNum + 1, !IO) :-
io.format("the argument #%d is %s\n", [i(ArgNum), s(Arg)], !IO).
|
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"
| #min | min | 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.)
| #EDSAC_order_code | EDSAC order code | [This is a comment]
[
And so
is
this
]
[But in 1949 they wouldn't have been] |
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.)
| #EGL | EGL | -- inline comment, continues until new 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.
| #jq | jq | # Notes on the implementation:
# 1. For efficiency, the implementation requires that the world
# has boundaries, as illustrated in the examples.
# 2. For speed, the simulation uses the exploded string.
# 3. The ASCII values of the "alive" and "empty" symbols are
# hardcoded: "." => 46; " " => 32
# 4. To adjust the refresh rate, adjust the input to "spin".
def lines: split("\n")|length;
def cols: split("\n")[0]|length + 1; # allow for the newline
# Is there a "." (46) at [x,y] relative to position i,
# assuming the width is w?
# Input is an array; result is 0 or 1 so we can easily count the total.
def isAlive(x; y; i; w): if .[i+ w*y + x] == 46 then 1 else 0 end;
def neighborhood(i;w):
isAlive(-1; -1; i; w) + isAlive(0; -1; i; w) + isAlive(1; -1; i; w) +
isAlive(-1; 0; i; w) + isAlive(1; 0; i; w) +
isAlive(-1; 1; i; w) + isAlive(0; 1; i; w) + isAlive(1; 1; i; w) ;
# The basic rules:
def evolve(cell; sum) :
if cell == 46 then if sum == 2 or sum == 3 then 46 else 32 end
elif cell == 32 then if sum == 3 then 46 else 32 end
else cell
end ;
# [world, lines, cols] | next(w) => [world, lines, cols]
def next:
.[0] as $world | .[1] as $lines | .[2] as $w
| reduce range(0; $world|length) as $i
($world;
.[$i] as $c
| if $c == 32 or $c == 46 then
# updates are "simultaneous" i.e. relative to $world, not "."
($world | neighborhood($i; $w)) as $sum
| evolve($c; $sum) as $next
| if $c == $next then . else .[$i] = $next end
else .
end )
| [., $lines, $w] ;
|
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.
| #Deluge | Deluge | if (input.Field == "Hello World") {
sVar = "good";
} else if (input.Field == "Bye World") {
sVar = "bad";
} else {
sVar = "neutral";
} |
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
| #Python | Python | all(a == nexta for a, nexta in zip(strings, strings[1:])) # All equal
all(a < nexta for a, nexta in zip(strings, strings[1:])) # Strictly ascending
len(set(strings)) == 1 # Concise all equal
sorted(strings, reverse=True) == strings # Concise (but not particularly efficient) ascending
|
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
| #Quackery | Quackery | [ [ true swap
dup size 1 > while
behead swap
witheach
[ over != if
[ dip not conclude ] ] ]
drop ] is allthesame ( [ --> b )
[ [ true swap
dup size 1 > while
behead swap
witheach
[ tuck $> if
[ dip not conclude ] ] ]
drop ] is allinorder ( [ --> b ) |
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.
| #jq | jq | def quibble:
if length == 0 then ""
elif length == 1 then .[0]
else (.[0:length-1] | join(", ")) + " and " + .[length-1]
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.
| #Julia | Julia | function quibble(arr::Array)
if isempty(arr) rst = "" else rst = "$(arr[end])" end
if length(arr) > 1 rst = join(arr[1:end-1], ", ") * " and " * rst end
return "{" * rst * "}"
end
@show quibble([])
@show quibble(["ABC"])
@show quibble(["ABC", "DEF"])
@show 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
| #PureBasic | PureBasic | Procedure nextCombination(Array combIndex(1), elementCount)
;combIndex() must be dimensioned to 'k' - 1, elementCount equals 'n' - 1
;combination produced includes repetition of elements and is represented by the array combIndex()
Protected i, indexValue, combSize = ArraySize(combIndex()), curIndex
;update indexes
curIndex = combSize
Repeat
combIndex(curIndex) + 1
If combIndex(curIndex) > elementCount
curIndex - 1
If curIndex < 0
For i = 0 To combSize
combIndex(i) = 0
Next
ProcedureReturn #False ;array reset to first combination
EndIf
ElseIf curIndex < combSize
indexValue = combIndex(curIndex)
Repeat
curIndex + 1
combIndex(curIndex) = indexValue
Until curIndex = combSize
EndIf
Until curIndex = combSize
ProcedureReturn #True ;array contains next combination
EndProcedure
Procedure.s display(Array combIndex(1), Array dougnut.s(1))
Protected i, elementCount = ArraySize(combIndex()), output.s = " "
For i = 0 To elementCount
output + dougnut(combIndex(i)) + " + "
Next
ProcedureReturn Left(output, Len(output) - 3)
EndProcedure
DataSection
Data.s "iced", "jam", "plain"
EndDataSection
If OpenConsole()
Define n = 3, k = 2, i, combinationCount
Dim combIndex(k - 1)
Dim dougnut.s(n - 1)
For i = 0 To n - 1: Read.s dougnut(i): Next
PrintN("Combinations of " + Str(n) + " dougnut types taken " + Str(k) + " at a time with repetitions.")
combinationCount = 0
Repeat
PrintN(display(combIndex(), dougnut()))
combinationCount + 1
Until Not nextCombination(combIndex(), n - 1)
PrintN("Total combination count: " + Str(combinationCount))
;extra credit
n = 10: k = 3
Dim combIndex(k - 1)
combinationCount = 0
Repeat: combinationCount + 1: Until Not nextCombination(combIndex(), n - 1)
PrintN(#CRLF$ + "Ways to select " + Str(k) + " items from " + Str(n) + " types: " + Str(combinationCount))
Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input()
CloseConsole()
EndIf |
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
| #Prolog | Prolog | /*
Test harness for the analyzer, not needed if we are actually using the output.
*/
load_file(File, Input) :-
read_file_to_codes(File, Codes, []),
maplist(char_code, Chars, Codes),
atom_chars(Input,Chars).
test_file(File) :-
load_file(File, Input),
tester(Input).
tester(S) :-
atom_chars(S,Chars),
tokenize(Chars,L),
maplist(print_tok, L),
!.
print_tok(L) :-
L =.. [Op,Line,Pos],
format('~d\t~d\t~p~n', [Line,Pos,Op]).
print_tok(string(Value,Line,Pos)) :-
format('~d\t~d\tstring\t\t"~w"~n', [Line,Pos,Value]).
print_tok(identifier(Value,Line,Pos)) :-
format('~d\t~d\tidentifier\t~p~n', [Line,Pos,Value]).
print_tok(integer(Value,Line,Pos)) :-
format('~d\t~d\tinteger\t\t~p~n', [Line,Pos,Value]).
/*
Tokenize
run the input over a DCG to get out the tokens.
In - a list of chars to tokenize
Tokens = a list of tokens (excluding spaces).
*/
tokenize(In,RelTokens) :-
newline_positions(In,1,NewLines),
tokenize(In,[0|NewLines],1,1,Tokens),
check_for_exceptions(Tokens),
exclude(token_name(space),Tokens,RelTokens).
tokenize([],NewLines,Pos,LineNo,[end_of_input(LineNo,Offset)]) :-
position_offset(NewLines,Pos,Offset).
tokenize(In,NewLines,Pos,LineNo,Out) :-
position_offset(NewLines,Pos,Offset),
phrase(tok(Tok,TokLen,LineNo,Offset),In,T),
(
Tok = [] -> Out = Toks
; Out = [Tok|Toks]
),
Pos1 is Pos + TokLen,
update_line_no(LineNo,NewLines,Pos1,NewLineNo,NewNewLines),
tokenize(T,NewNewLines,Pos1,NewLineNo,Toks).
update_line_no(LNo,[L],_,LNo,[L]).
update_line_no(LNo,[L,Nl|T],Pos,LNo,[L,Nl|T]) :-
Pos =< Nl.
update_line_no(LNo,[_,Nl|T],Pos,LNo2,Nlines) :-
Pos > Nl,
succ(LNo,LNo1),
update_line_no(LNo1,[Nl|T],Pos,LNo2,Nlines).
position_offset([Line|_],Pos,Offset) :- Offset is Pos - Line.
token_name(Name,Tok) :- functor(Tok,Name,_).
% Get a list of all the newlines and their position in the data
% This is used to create accurate row/column numbers.
newline_positions([],N,[N]).
newline_positions(['\n'|T],N,[N|Nt]) :- succ(N,N1), newline_positions(T,N1,Nt).
newline_positions([C|T],N,Nt) :- dif(C,'\n'), succ(N,N1), newline_positions(T,N1,Nt).
% The tokenizer can tokenize some things that it shouldn't, deal with them here.
check_for_exceptions([]). % all ok
check_for_exceptions([op_divide(L,P),op_multiply(_,_)|_]) :-
format(atom(Error), 'Unclosed comment at line ~d,~d', [L,P]),
throw(Error).
check_for_exceptions([integer(_,L,P),identifier(_,_,_)|_]) :-
format(atom(Error), 'Invalid identifier at line ~d,~d', [L,P]),
throw(Error).
check_for_exceptions([_|T]) :- check_for_exceptions(T).
/*
A set of helper DCGs for the more complicated token types
*/
:- set_prolog_flag(double_quotes, chars).
identifier(I) --> c_types(I,csym).
identifier(['_']) --> ['_'].
identifier([]) --> [].
integer_(I,L) --> c_types(N,digit), { number_codes(I,N), length(N,L) }.
% get a sequence of characters of the same type (https://www.swi-prolog.org/pldoc/doc_for?object=char_type/2)
c_types([C|T],Type) --> c_type(C,Type), c_types(T,Type).
c_types([C],Type) --> c_type(C,Type).
c_type(C,Type) --> [C],{ char_type(C,Type) }.
anything([]) --> [].
anything([A|T]) --> [A], anything(T).
string_([]) --> [].
string_([A|T]) --> [A], { dif(A,'\n') }, string_(T).
/*
The token types are all handled by the tok DCG, order of predicates is important here.
*/
% comment
tok([],CLen,_,_) --> "/*", anything(A), "*/", { length(A,Len), CLen is Len + 4 }.
% toks
tok(op_and(L,P),2,L,P) --> "&&".
tok(op_or(L,P),2,L,P) --> "||".
tok(op_lessequal(L,P),2,L,P) --> "<=".
tok(op_greaterequal(L,P),2,L,P) --> ">=".
tok(op_greaterequal(L,P),2,L,P) --> ">=".
tok(op_equal(L,P),2,L,P) --> "==".
tok(op_notequal(L,P),2,L,P) --> "!=".
tok(op_assign(L,P),1,L,P) --> "=".
tok(op_multiply(L,P),1,L,P) --> "*".
tok(op_divide(L,P),1,L,P) --> "/".
tok(op_mod(L,P),1,L,P) --> "%".
tok(op_add(L,P),1,L,P) --> "+".
tok(op_subtract(L,P),1,L,P) --> "-".
tok(op_negate(L,P),1,L,P) --> "-".
tok(op_less(L,P),1,L,P) --> "<".
tok(op_greater(L,P),1,L,P) --> ">".
tok(op_not(L,P),1,L,P) --> "!".
% symbols
tok(left_paren(L,P),1,L,P) --> "(".
tok(right_paren(L,P),1,L,P) --> ")".
tok(left_brace(L,P),1,L,P) --> "{".
tok(right_brace(L,P),1,L,P) --> "}".
tok(semicolon(L,P),1,L,P) --> ";".
tok(comma(L,P),1,L,P) --> ",".
% keywords
tok(keyword_if(L,P),2,L,P) --> "if".
tok(keyword_else(L,P),4,L,P) --> "else".
tok(keyword_while(L,P),5,L,P) --> "while".
tok(keyword_print(L,P),5,L,P) --> "print".
tok(keyword_putc(L,P),4,L,P) --> "putc".
% identifier and literals
tok(identifier(I,L,P),Len,L,P) --> c_type(S,csymf), identifier(T), { atom_chars(I,[S|T]), length([S|T],Len) }.
tok(integer(V,L,P),Len,L,P) --> integer_(V,Len).
tok(integer(I,L,P),4,L,P) --> "'\\\\'", { char_code('\\', I) }.
tok(integer(I,L,P),4,L,P) --> "'\\n'", { char_code('\n', I) }.
tok(integer(I,L,P),3,L,P) --> ['\''], [C], ['\''], { dif(C,'\n'), dif(C,'\''), char_code(C,I) }.
tok(string(S,L,P),SLen,L,P) --> ['"'], string_(A),['"'], { atom_chars(S,A), length(A,Len), SLen is Len + 2 }.
% spaces
tok(space(L,P),Len,L,P) --> c_types(S,space), { length(S,Len) }.
% anything else is an error
tok(_,_,L,P) --> { format(atom(Error), 'Invalid token at line ~d,~d', [L,P]), throw(Error) }. |
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"
| #MMIX | MMIX | argv IS $1
argc IS $0
i IS $2
LOC #100
Main LOC @
SETL i,1 % i = 1
Loop CMP $3,argc,2 % argc < 2 ?
BN $3,1F % then jump to end
XOR $255,$255,$255 % clear $255
8ADDU $255,i,argv % i*8 + argv
LDOU $255,$255,0 % argv[i]
TRAP 0,Fputs,StdOut % write the argument
GETA $255,NewLine % add a newline
TRAP 0,Fputs,StdOut
INCL i,1 % increment index
SUB argc,argc,1 % argc--
BP argc,Loop % argc > 0? then Loop
1H LOC @
XOR $255,$255,$255 % exit(0)
TRAP 0,Halt,0
NewLine BYTE #a,0 |
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"
| #Modula-2 | Modula-2 | MODULE try;
FROM Arguments IMPORT GetArgs, ArgTable, GetEnv;
FROM InOut IMPORT WriteCard, WriteLn, WriteString;
VAR count, item : SHORTCARD;
storage : ArgTable;
BEGIN
GetArgs (count, storage);
WriteString ('Count ='); WriteCard (count, 4); WriteLn;
item := 0;
REPEAT
WriteCard (item, 4);
WriteString (' : ');
WriteString (storage^ [item]^);
WriteLn;
INC (item)
UNTIL item = count
END try. |
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.)
| #Eiffel | Eiffel | -- inline comment, continues until new line |
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.)
| #Ela | Ela | //single line comment
/*multiple 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.
| #Jsish | Jsish | /* Conway's game of life, in Jsish */
function GameOfLife () {
this.title = "Conway's Game of Life";
this.cls = "\u001B[H\u001B[2J";
this.init = function (turns, width, height) {
this.board = new Array(height);
for (var x = 0; x < height; x++) {
this.board[x] = new Array(width);
for (var y = 0; y < width; y++) {
this.board[x][y] = Math.round(Math.random());
}
}
this.turns = turns;
};
this.nextGen = function() {
this.boardNext = new Array(this.board.length);
for (var i = 0; i < this.board.length; i++) {
this.boardNext[i] = new Array(this.board[i].length);
}
for (var x = 0; x < this.board.length; x++) {
for (var y = 0; y < this.board[x].length; y++) {
var n = 0;
for (var dx = -1; dx <= 1; dx++) {
for (var dy = -1; dy <= 1; dy++) {
if ( dx == 0 && dy == 0){}
else if (typeof this.board[x+dx] !== 'undefined'
&& typeof this.board[x+dx][y+dy] !== 'undefined'
&& this.board[x+dx][y+dy]) {
n++;
}
}
}
var c = this.board[x][y];
switch (n) {
case 0:
case 1:
c = 0;
break;
case 2:
break;
case 3:
c = 1;
break;
default:
c = 0;
}
this.boardNext[x][y] = c;
}
}
this.board = this.boardNext.slice(0);
};
this.print = function() {
for (var x = 0; x < this.board.length; x++) {
var l = "";
for (var y = 0; y < this.board[x].length; y++) {
if (this.board[x][y])
l += "X";
else
l += " ";
}
puts(l);
}
};
this.start = function() {
for (var t = 0; t < this.turns; t++) {
sleep(500);
printf(this.cls);
puts(this.title + "\n---\nTurn "+(t+1));
this.print();
this.nextGen();
}
};
}
var game = new GameOfLife();
if (Interp.conf('unitTest')) {
game.init(3,3,3);
game.title="---\n3x3 Blinker over three turns.";
game.board = [
[0,0,0],
[1,1,1],
[0,0,0]];
game.cls="";
game.start();
} else {
game.init(3,3,3);
game.title="---\n3x3 Blinker over three turns.";
game.board = [
[0,0,0],
[1,1,1],
[0,0,0]];
game.start();
game.init(5,10,6);
game.title="---\n10x6 Glider over five turns.";
game.board = [
[0,0,0,0,0,0,0,0,0,0],
[0,0,1,0,0,0,0,0,0,0],
[0,0,0,1,0,0,0,0,0,0],
[0,1,1,1,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0]];
game.start();
var steps = (console.args[0]) ? parseInt(console.args[0]) || 1 : 50;
game.init(steps, 32,16);
game.title="---\nRandom 32x16, " + steps + " step" + ((steps === 1) ? "" : "s");
game.start();
}
/*
=!EXPECTSTART!=
---
3x3 Blinker over three turns.
---
Turn 1
XXX
---
3x3 Blinker over three turns.
---
Turn 2
X
X
X
---
3x3 Blinker over three turns.
---
Turn 3
XXX
=!EXPECTEND!=
*/ |
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.
| #DM | DM | if (condition)
// Do thing, DM uses indentation for control flow.
if (condition)
// Do thing
else if (condition)
// Do thing
else
// Do thing
|
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
| #R | R |
chunks <- function (compare, xs) {
starts = which(c(T, !compare(head(xs, -1), xs[-1]), T))
lapply(seq(1,length(starts)-1),
function(i) xs[starts[i]:(starts[i+1]-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
| #Racket | Racket | #lang racket/base
(define ((list-stringX? stringX?) strs)
(or (null? strs) (null? (cdr strs)) (apply stringX? strs)))
(define list-string=? (list-stringX? string=?))
(define list-string<? (list-stringX? string<?))
(module+ test
(require tests/eli-tester)
(test
(list-string=? '()) => #t
(list-string=? '("a")) => #t
(list-string=? '("a" "a")) => #t
(list-string=? '("a" "a" "a")) => #t
(list-string=? '("b" "b" "a")) => #f)
(test
(list-string<? '()) => #t
(list-string<? '("a")) => #t
(list-string<? '("a" "b")) => #t
(list-string<? '("a" "a")) => #f
(list-string<? '("a" "b" "a")) => #f
(list-string<? '("a" "b" "c")) => #t)) |
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.
| #Kotlin | Kotlin | // version 1.0.6
fun commaQuibble(s: String): String {
val t = s.trim('[', ']').replace(" ", "").replace("\"", "")
val words = t.split(',')
val sb = StringBuilder("{")
for (i in 0 until words.size) {
sb.append(when (i) {
0 -> ""
words.lastIndex -> " and "
else -> ", "
})
sb.append(words[i])
}
return sb.append("}").toString()
}
fun main(args: Array<String>) {
val inputs = arrayOf(
"""[]""",
"""["ABC"]""",
"""["ABC", "DEF"]""",
"""["ABC", "DEF", "G", "H"]"""
)
for (input in inputs) println("${input.padEnd(24)} -> ${commaQuibble(input)}")
} |
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
| #Python | Python | >>> from itertools import combinations_with_replacement
>>> n, k = 'iced jam plain'.split(), 2
>>> list(combinations_with_replacement(n,k))
[('iced', 'iced'), ('iced', 'jam'), ('iced', 'plain'), ('jam', 'jam'), ('jam', 'plain'), ('plain', 'plain')]
>>> # Extra credit
>>> len(list(combinations_with_replacement(range(10), 3)))
220
>>> |
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
| #Quackery | Quackery | ( nextplain generates the next plaindrome in the
current base by adding one to a given plaindrome,
then replacing each trailing zero with the least
significant non-zero digit of the number
See: https://oeis.org/search?q=plaindromes
4 base put
-1
10 times
[ nextplain
dup echo sp ]
drop
base release
prints "0 1 2 3 11 12 13 22 23 33"
i.e. decimal "0 1 2 3 5 6 7 10 11 15"
Right padding the base 4 representations with
zeros gives all the combinations with repetitions
for selecting two doughnuts in a store selling
four types of doughnut, numbered 0, 1, 2, and 3.
00 01 02 03 11 12 13 22 23 33 )
[ 1+ dup 0 = if done
0 swap
[ base share /mod
dup 0 = while
drop dip 1+
again ]
swap rot 1+ times
[ base share * over + ]
nip ] is nextplain ( n --> n )
[ dup base put
swap ** 1 -
[] swap -1
[ 2dup > while
nextplain
rot over join
unrot
again ]
base release
2drop ] is kcombnums ( n n --> [ )
[ [] unrot times
[ base share /mod
rot join swap ]
drop ] is ndigits ( n n --> [ )
[ [] unrot
witheach
[ dip dup peek
nested rot swap join
swap ]
drop ] is [peek] ( [ [ --> [ )
[ dup temp put
size dup base put
dip dup kcombnums
[] unrot witheach
[ over ndigits
temp share swap [peek]
nested rot swap join
swap ]
temp release
base release
drop ] is kcombs ( n [ --> [ )
2
$ "jam iced plain" nest$
kcombs
witheach
[ witheach
[ echo$ sp ] cr ]
cr
3 10 kcombnums size echo |
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
| #Python | Python | from __future__ import print_function
import sys
# following two must remain in the same order
tk_EOI, tk_Mul, tk_Div, tk_Mod, tk_Add, tk_Sub, tk_Negate, tk_Not, tk_Lss, tk_Leq, tk_Gtr, \
tk_Geq, tk_Eq, tk_Neq, tk_Assign, tk_And, tk_Or, tk_If, tk_Else, tk_While, tk_Print, \
tk_Putc, tk_Lparen, tk_Rparen, tk_Lbrace, tk_Rbrace, tk_Semi, tk_Comma, tk_Ident, \
tk_Integer, tk_String = range(31)
all_syms = ["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"]
# single character only symbols
symbols = { '{': tk_Lbrace, '}': tk_Rbrace, '(': tk_Lparen, ')': tk_Rparen, '+': tk_Add, '-': tk_Sub,
'*': tk_Mul, '%': tk_Mod, ';': tk_Semi, ',': tk_Comma }
key_words = {'if': tk_If, 'else': tk_Else, 'print': tk_Print, 'putc': tk_Putc, 'while': tk_While}
the_ch = " " # dummy first char - but it must be a space
the_col = 0
the_line = 1
input_file = None
#*** show error and exit
def error(line, col, msg):
print(line, col, msg)
exit(1)
#*** get the next character from the input
def next_ch():
global the_ch, the_col, the_line
the_ch = input_file.read(1)
the_col += 1
if the_ch == '\n':
the_line += 1
the_col = 0
return the_ch
#*** 'x' - character constants
def char_lit(err_line, err_col):
n = ord(next_ch()) # skip opening quote
if the_ch == '\'':
error(err_line, err_col, "empty character constant")
elif the_ch == '\\':
next_ch()
if the_ch == 'n':
n = 10
elif the_ch == '\\':
n = ord('\\')
else:
error(err_line, err_col, "unknown escape sequence \\%c" % (the_ch))
if next_ch() != '\'':
error(err_line, err_col, "multi-character constant")
next_ch()
return tk_Integer, err_line, err_col, n
#*** process divide or comments
def div_or_cmt(err_line, err_col):
if next_ch() != '*':
return tk_Div, err_line, err_col
# comment found
next_ch()
while True:
if the_ch == '*':
if next_ch() == '/':
next_ch()
return gettok()
elif len(the_ch) == 0:
error(err_line, err_col, "EOF in comment")
else:
next_ch()
#*** "string"
def string_lit(start, err_line, err_col):
global the_ch
text = ""
while next_ch() != start:
if len(the_ch) == 0:
error(err_line, err_col, "EOF while scanning string literal")
if the_ch == '\n':
error(err_line, err_col, "EOL while scanning string literal")
if the_ch == '\\':
next_ch()
if the_ch != 'n':
error(err_line, err_col, "escape sequence unknown \\%c" % the_ch)
the_ch = '\n'
text += the_ch
next_ch()
return tk_String, err_line, err_col, text
#*** handle identifiers and integers
def ident_or_int(err_line, err_col):
is_number = True
text = ""
while the_ch.isalnum() or the_ch == '_':
text += the_ch
if not the_ch.isdigit():
is_number = False
next_ch()
if len(text) == 0:
error(err_line, err_col, "ident_or_int: unrecognized character: (%d) '%c'" % (ord(the_ch), the_ch))
if text[0].isdigit():
if not is_number:
error(err_line, err_col, "invalid number: %s" % (text))
n = int(text)
return tk_Integer, err_line, err_col, n
if text in key_words:
return key_words[text], err_line, err_col
return tk_Ident, err_line, err_col, text
#*** look ahead for '>=', etc.
def follow(expect, ifyes, ifno, err_line, err_col):
if next_ch() == expect:
next_ch()
return ifyes, err_line, err_col
if ifno == tk_EOI:
error(err_line, err_col, "follow: unrecognized character: (%d) '%c'" % (ord(the_ch), the_ch))
return ifno, err_line, err_col
#*** return the next token type
def gettok():
while the_ch.isspace():
next_ch()
err_line = the_line
err_col = the_col
if len(the_ch) == 0: return tk_EOI, err_line, err_col
elif the_ch == '/': return div_or_cmt(err_line, err_col)
elif the_ch == '\'': return char_lit(err_line, err_col)
elif the_ch == '<': return follow('=', tk_Leq, tk_Lss, err_line, err_col)
elif the_ch == '>': return follow('=', tk_Geq, tk_Gtr, err_line, err_col)
elif the_ch == '=': return follow('=', tk_Eq, tk_Assign, err_line, err_col)
elif the_ch == '!': return follow('=', tk_Neq, tk_Not, err_line, err_col)
elif the_ch == '&': return follow('&', tk_And, tk_EOI, err_line, err_col)
elif the_ch == '|': return follow('|', tk_Or, tk_EOI, err_line, err_col)
elif the_ch == '"': return string_lit(the_ch, err_line, err_col)
elif the_ch in symbols:
sym = symbols[the_ch]
next_ch()
return sym, err_line, err_col
else: return ident_or_int(err_line, err_col)
#*** main driver
input_file = sys.stdin
if len(sys.argv) > 1:
try:
input_file = open(sys.argv[1], "r", 4096)
except IOError as e:
error(0, 0, "Can't open %s" % sys.argv[1])
while True:
t = gettok()
tok = t[0]
line = t[1]
col = t[2]
print("%5d %5d %-14s" % (line, col, all_syms[tok]), end='')
if tok == tk_Integer: print(" %5d" % (t[3]))
elif tok == tk_Ident: print(" %s" % (t[3]))
elif tok == tk_String: print(' "%s"' % (t[3]))
else: print("")
if tok == tk_EOI:
break |
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"
| #Modula-3 | Modula-3 | MODULE Args EXPORTS Main;
IMPORT IO, Params;
BEGIN
IO.Put(Params.Get(0) & "\n");
IF Params.Count > 1 THEN
FOR i := 1 TO Params.Count - 1 DO
IO.Put(Params.Get(i) & "\n");
END;
END;
END 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"
| #Nanoquery | Nanoquery | //
// command-line arguments
//
// output all arguments
for i in range(0, len(args) - 1)
println args[i]
end |
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