Spaces:
Sleeping
Sleeping
File size: 10,780 Bytes
ffaa9fc |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 |
#
# Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
# Use of this file is governed by the BSD 3-clause license that
# can be found in the LICENSE.txt file in the project root.
# This implementation of {@link TokenStream} loads tokens from a
# {@link TokenSource} on-demand, and places the tokens in a buffer to provide
# access to any previous token by index.
#
# <p>
# This token stream ignores the value of {@link Token#getChannel}. If your
# parser requires the token stream filter tokens to only those on a particular
# channel, such as {@link Token#DEFAULT_CHANNEL} or
# {@link Token#HIDDEN_CHANNEL}, use a filtering token stream such a
# {@link CommonTokenStream}.</p>
from io import StringIO
from antlr4.Token import Token
from antlr4.error.Errors import IllegalStateException
# need forward declaration
Lexer = None
# this is just to keep meaningful parameter types to Parser
class TokenStream(object):
pass
class BufferedTokenStream(TokenStream):
__slots__ = ('tokenSource', 'tokens', 'index', 'fetchedEOF')
def __init__(self, tokenSource:Lexer):
# The {@link TokenSource} from which tokens for this stream are fetched.
self.tokenSource = tokenSource
# A collection of all tokens fetched from the token source. The list is
# considered a complete view of the input once {@link #fetchedEOF} is set
# to {@code true}.
self.tokens = []
# The index into {@link #tokens} of the current token (next token to
# {@link #consume}). {@link #tokens}{@code [}{@link #p}{@code ]} should be
# {@link #LT LT(1)}.
#
# <p>This field is set to -1 when the stream is first constructed or when
# {@link #setTokenSource} is called, indicating that the first token has
# not yet been fetched from the token source. For additional information,
# see the documentation of {@link IntStream} for a description of
# Initializing Methods.</p>
self.index = -1
# Indicates whether the {@link Token#EOF} token has been fetched from
# {@link #tokenSource} and added to {@link #tokens}. This field improves
# performance for the following cases:
#
# <ul>
# <li>{@link #consume}: The lookahead check in {@link #consume} to prevent
# consuming the EOF symbol is optimized by checking the values of
# {@link #fetchedEOF} and {@link #p} instead of calling {@link #LA}.</li>
# <li>{@link #fetch}: The check to prevent adding multiple EOF symbols into
# {@link #tokens} is trivial with this field.</li>
# <ul>
self.fetchedEOF = False
def mark(self):
return 0
def release(self, marker:int):
# no resources to release
pass
def reset(self):
self.seek(0)
def seek(self, index:int):
self.lazyInit()
self.index = self.adjustSeekIndex(index)
def get(self, index:int):
self.lazyInit()
return self.tokens[index]
def consume(self):
skipEofCheck = False
if self.index >= 0:
if self.fetchedEOF:
# the last token in tokens is EOF. skip check if p indexes any
# fetched token except the last.
skipEofCheck = self.index < len(self.tokens) - 1
else:
# no EOF token in tokens. skip check if p indexes a fetched token.
skipEofCheck = self.index < len(self.tokens)
else:
# not yet initialized
skipEofCheck = False
if not skipEofCheck and self.LA(1) == Token.EOF:
raise IllegalStateException("cannot consume EOF")
if self.sync(self.index + 1):
self.index = self.adjustSeekIndex(self.index + 1)
# Make sure index {@code i} in tokens has a token.
#
# @return {@code true} if a token is located at index {@code i}, otherwise
# {@code false}.
# @see #get(int i)
#/
def sync(self, i:int):
n = i - len(self.tokens) + 1 # how many more elements we need?
if n > 0 :
fetched = self.fetch(n)
return fetched >= n
return True
# Add {@code n} elements to buffer.
#
# @return The actual number of elements added to the buffer.
#/
def fetch(self, n:int):
if self.fetchedEOF:
return 0
for i in range(0, n):
t = self.tokenSource.nextToken()
t.tokenIndex = len(self.tokens)
self.tokens.append(t)
if t.type==Token.EOF:
self.fetchedEOF = True
return i + 1
return n
# Get all tokens from start..stop inclusively#/
def getTokens(self, start:int, stop:int, types:set=None):
if start<0 or stop<0:
return None
self.lazyInit()
subset = []
if stop >= len(self.tokens):
stop = len(self.tokens)-1
for i in range(start, stop):
t = self.tokens[i]
if t.type==Token.EOF:
break
if types is None or t.type in types:
subset.append(t)
return subset
def LA(self, i:int):
return self.LT(i).type
def LB(self, k:int):
if (self.index-k) < 0:
return None
return self.tokens[self.index-k]
def LT(self, k:int):
self.lazyInit()
if k==0:
return None
if k < 0:
return self.LB(-k)
i = self.index + k - 1
self.sync(i)
if i >= len(self.tokens): # return EOF token
# EOF must be last token
return self.tokens[len(self.tokens)-1]
return self.tokens[i]
# Allowed derived classes to modify the behavior of operations which change
# the current stream position by adjusting the target token index of a seek
# operation. The default implementation simply returns {@code i}. If an
# exception is thrown in this method, the current stream index should not be
# changed.
#
# <p>For example, {@link CommonTokenStream} overrides this method to ensure that
# the seek target is always an on-channel token.</p>
#
# @param i The target token index.
# @return The adjusted target token index.
def adjustSeekIndex(self, i:int):
return i
def lazyInit(self):
if self.index == -1:
self.setup()
def setup(self):
self.sync(0)
self.index = self.adjustSeekIndex(0)
# Reset this token stream by setting its token source.#/
def setTokenSource(self, tokenSource:Lexer):
self.tokenSource = tokenSource
self.tokens = []
self.index = -1
self.fetchedEOF = False
# Given a starting index, return the index of the next token on channel.
# Return i if tokens[i] is on channel. Return the index of the EOF token
# if there are no tokens on channel between i and EOF.
#/
def nextTokenOnChannel(self, i:int, channel:int):
self.sync(i)
if i>=len(self.tokens):
return len(self.tokens) - 1
token = self.tokens[i]
while token.channel!=channel:
if token.type==Token.EOF:
return i
i += 1
self.sync(i)
token = self.tokens[i]
return i
# Given a starting index, return the index of the previous token on channel.
# Return i if tokens[i] is on channel. Return -1 if there are no tokens
# on channel between i and 0.
def previousTokenOnChannel(self, i:int, channel:int):
while i>=0 and self.tokens[i].channel!=channel:
i -= 1
return i
# Collect all tokens on specified channel to the right of
# the current token up until we see a token on DEFAULT_TOKEN_CHANNEL or
# EOF. If channel is -1, find any non default channel token.
def getHiddenTokensToRight(self, tokenIndex:int, channel:int=-1):
self.lazyInit()
if tokenIndex<0 or tokenIndex>=len(self.tokens):
raise Exception(str(tokenIndex) + " not in 0.." + str(len(self.tokens)-1))
from antlr4.Lexer import Lexer
nextOnChannel = self.nextTokenOnChannel(tokenIndex + 1, Lexer.DEFAULT_TOKEN_CHANNEL)
from_ = tokenIndex+1
# if none onchannel to right, nextOnChannel=-1 so set to = last token
to = (len(self.tokens)-1) if nextOnChannel==-1 else nextOnChannel
return self.filterForChannel(from_, to, channel)
# Collect all tokens on specified channel to the left of
# the current token up until we see a token on DEFAULT_TOKEN_CHANNEL.
# If channel is -1, find any non default channel token.
def getHiddenTokensToLeft(self, tokenIndex:int, channel:int=-1):
self.lazyInit()
if tokenIndex<0 or tokenIndex>=len(self.tokens):
raise Exception(str(tokenIndex) + " not in 0.." + str(len(self.tokens)-1))
from antlr4.Lexer import Lexer
prevOnChannel = self.previousTokenOnChannel(tokenIndex - 1, Lexer.DEFAULT_TOKEN_CHANNEL)
if prevOnChannel == tokenIndex - 1:
return None
# if none on channel to left, prevOnChannel=-1 then from=0
from_ = prevOnChannel+1
to = tokenIndex-1
return self.filterForChannel(from_, to, channel)
def filterForChannel(self, left:int, right:int, channel:int):
hidden = []
for i in range(left, right+1):
t = self.tokens[i]
if channel==-1:
from antlr4.Lexer import Lexer
if t.channel!= Lexer.DEFAULT_TOKEN_CHANNEL:
hidden.append(t)
elif t.channel==channel:
hidden.append(t)
if len(hidden)==0:
return None
return hidden
def getSourceName(self):
return self.tokenSource.getSourceName()
# Get the text of all tokens in this buffer.#/
def getText(self, start:int=None, stop:int=None):
self.lazyInit()
self.fill()
if isinstance(start, Token):
start = start.tokenIndex
elif start is None:
start = 0
if isinstance(stop, Token):
stop = stop.tokenIndex
elif stop is None or stop >= len(self.tokens):
stop = len(self.tokens) - 1
if start < 0 or stop < 0 or stop < start:
return ""
with StringIO() as buf:
for i in range(start, stop+1):
t = self.tokens[i]
if t.type==Token.EOF:
break
buf.write(t.text)
return buf.getvalue()
# Get all tokens from lexer until EOF#/
def fill(self):
self.lazyInit()
while self.fetch(1000)==1000:
pass
|