def getNextToken(self):
if not self._instream:
return None
if self._stack:
return self._stack.pop()
consumed = ""
startLine = 0
startColumn = 0
if not self._inputBuffer:
# Puffer erzeugen. Größe auf Zwei setzen, um evtl. Escape-Zeichen erkennen zu können
self._inputBuffer = InputBuffer(self._instream, fillSize=2)
while True:
content = self._inputBuffer.getContent()
if not content:
break
consumedChars, isTermination = self._consume()
curStartPos = self._updatePosInfo(consumedChars)
if self._mode == LexerMode.NORMAL:
if not consumed and curStartPos:
startLine = curStartPos[0]
startColumn = curStartPos[1]
consumed += consumedChars
if isTermination:
if self._mode == LexerMode.NORMAL:
res = self._handleComsumption(consumed, startLine, startColumn)
if res:
return res
else:
consumed = ""
else: # Kommentarmodus => Moduswechsel mit Content prüfen
self._checkForModeChange(content)
if consumed:
return self._handleComsumption(consumed, startLine, startColumn)
else:
return None
def _checkForModeChange(self,consumed):
res = consumed
if not consumed:
return res
if self._mode == LexerMode.NORMAL:
if self._lineCommentEnabled and \
self._matchesCommentBegin(consumed, self._lineCommentStart):
self._mode = LexerMode.LINE_COMMENT
self._inputBuffer = InputBuffer(self._instream,
fillSize = 1 # <- Länge von '\n'
)
res = ""
elif self._blockCommentEnabled and \
self._matchesCommentBegin(consumed, self._blockCommentStart):
self._mode = LexerMode.BLOCK_COMMENT
size = len(self._blockCommentEnd);
self._inputBuffer = InputBuffer(self._instream,
fillSize = size
)
res = ""
else:
self._mode = LexerMode.NORMAL
self._inputBuffer = InputBuffer(self._instream,
fillSize = 2 # <- Länge zwei wg. Escape-Zeichen
)
res = ""
return res
class Lexer(object):
def __init__(self):
self._instream = None
self._stack = []
self._keywords = {}
self._words = []
self._prefixes = []
self._postfixes = []
self._separators = []
self._literal = None
self._literalDelims = []
self._literalEscChar = None
self._currentLitDelim = ''
self._wsCharCodes = [
WSCharCode.TAB,
WSCharCode.LINEBREAK,
WSCharCode.VTAB,
WSCharCode.FORMFEED,
WSCharCode.SPACE
]
self._mode = LexerMode.NORMAL
self._lineCommentEnabled = False
self._lineCommentStart = ''
self._blockCommentEnabled = False
self._blockCommentStart = ''
self._blockCommentEnd = ''
self._line = 1
self._column = 0
def setInputStream(self, instream):
self._instream = instream
self._reset()
def _reset(self):
self._stack = []
self._inputBuffer = None
self._mode = LexerMode.NORMAL
self._line = 1
self._column = 0
def addTokenType(self, tt):
if isinstance(tt, Keyword):
self._keywords[tt.getKeyword()] = tt
elif isinstance(tt, Word):
self._words.append(tt)
elif isinstance(tt, Prefix):
self._prefixes.append(tt)
self._prefixes.sort(cmp=TokenType.compare)
elif isinstance(tt, Postfix):
self._postfixes.append(tt)
self._postfixes.sort(cmp=TokenType.compare)
elif isinstance(tt, Separator):
self._separators.append(tt)
self._separators.sort(cmp=TokenType.compare)
elif isinstance(tt, Literal):
self._literal = tt
self._literalDelims = tt.DELIMITERS
self._literalEscChar = Literal.ESCAPE_CHAR
else:
raise Exception('Unknown token type')
def enableLineComments(self, lineCommentStart='//'):
self._lineCommentEnabled = True
self._lineCommentStart = lineCommentStart
def enableBlockComments(self,
blockCommentStart='/*',
blockCommentEnd='*/'):
self._blockCommentEnabled = True
self._blockCommentStart = blockCommentStart
self._blockCommentEnd = blockCommentEnd
def getNextToken(self):
if not self._instream:
return None
if self._stack:
return self._stack.pop()
consumed = ""
startLine = 0
startColumn = 0
if not self._inputBuffer:
# Puffer erzeugen. Größe auf Zwei setzen, um evtl. Escape-Zeichen erkennen zu können
self._inputBuffer = InputBuffer(self._instream, fillSize=2)
while True:
content = self._inputBuffer.getContent()
if not content:
break
consumedChars, isTermination = self._consume()
curStartPos = self._updatePosInfo(consumedChars)
if self._mode == LexerMode.NORMAL:
if not consumed and curStartPos:
startLine = curStartPos[0]
startColumn = curStartPos[1]
consumed += consumedChars
if isTermination:
if self._mode == LexerMode.NORMAL:
res = self._handleComsumption(consumed, startLine, startColumn)
if res:
return res
else:
consumed = ""
else: # Kommentarmodus => Moduswechsel mit Content prüfen
self._checkForModeChange(content)
if consumed:
return self._handleComsumption(consumed, startLine, startColumn)
else:
return None
def _updatePosInfo(self, content):
res = None
for i in range(len(content)):
ch = content[i]
if not ord(ch) == WSCharCode.LINEBREAK:
self._column += 1
else:
self._line += 1
self._column = 0
if i == 0:
res = (self._line, self._column)
return res
def _checkForModeChange(self,consumed):
res = consumed
if not consumed:
return res
if self._mode == LexerMode.NORMAL:
if self._lineCommentEnabled and \
self._matchesCommentBegin(consumed, self._lineCommentStart):
self._mode = LexerMode.LINE_COMMENT
self._inputBuffer = InputBuffer(self._instream,
fillSize = 1 # <- Länge von '\n'
)
res = ""
elif self._blockCommentEnabled and \
self._matchesCommentBegin(consumed, self._blockCommentStart):
self._mode = LexerMode.BLOCK_COMMENT
size = len(self._blockCommentEnd);
self._inputBuffer = InputBuffer(self._instream,
fillSize = size
)
res = ""
else:
self._mode = LexerMode.NORMAL
self._inputBuffer = InputBuffer(self._instream,
fillSize = 2 # <- Länge zwei wg. Escape-Zeichen
)
res = ""
return res
def _getTokens(self, text, startLine, startColumn):
# Handle literals:
if self._literal:
token = self._literal.createToken(text)
if token:
token.setStartPosition(startLine, startColumn)
return [token]
res = []
# Find separators and split:
for sep in self._separators:
token = sep.createToken(text)
if token:
# Reihenfolge wg. POP-Logik vertauschen...
right = sep.getRemainingRight(text)
left = sep.getRemainingLeft(text)
if right:
col = startColumn + len(left) + len(token.getText())
res = self._getTokens(right, startLine, col)
token.setStartPosition(startLine, startColumn + len(left))
res.append(token)
if left:
res += self._getTokens(left, startLine, startColumn)
return res
# Find prefixes:
for prefix in self._prefixes:
token = prefix.createToken(text)
if token:
right = prefix.getRemainingRight(text)
if right:
col = startColumn + len(token.getText())
res = self._getTokens(right, startLine, col)
token.setStartPosition(startLine, startColumn)
res.append(token)
return res
# Find postfixes:
for postfix in self._postfixes:
token = postfix.createToken(text)
if token:
left = postfix.getRemainingLeft(text)
col = startColumn + len(left)
token.setStartPosition(startLine, col)
res.append(token)
if left:
res += self._getTokens(left, startLine, startColumn)
return res
# Find (key)words:
try:
matchingWords = [self._keywords[text]]
except KeyError:
# maybe case insensitive keyword?
try:
kw = self._keywords[text.upper()]
if not kw.isCaseSensitive():
matchingWords = [kw]
else:
matchingWords = []
except KeyError:
matchingWords = []
matchingWords += [word for word in self._words if word.matches(text)]
if matchingWords:
token = Token(text, matchingWords)
token.setStartPosition(startLine, startColumn)
res.append(token)
return res
raise Exception("Unknown token '%s' at line %d, column %d" % (text, startLine, startColumn))
def _handleComsumption(self, consumed, startLine, startColumn):
consumed = self._checkForModeChange(consumed)
if consumed:
self._stack = self._getTokens(consumed, startLine, startColumn)
if self._stack:
return self._stack.pop()
else:
raise Exception("Unknown token '%s' at line %d, column %d" \
% (consumed, startLine, startColumn))
return None
def _consume(self):
text = self._inputBuffer.getContent()
if not text:
raise Exception('Must not consume empty content')
if self._mode == LexerMode.NORMAL:
isTermination = False
consumed = ''
textLen = len(text)
lastIdx = textLen - 1
prevChar = None
for idx in range(textLen):
ch = text[idx]
if idx != lastIdx or ch != self._literalEscChar or textLen == 1:
consumedChar = self._inputBuffer.consumeChar()
if prevChar is None or prevChar != self._literalEscChar:
isTermination = self._isWhiteSpace(consumedChar)
if isTermination:
break
consumed += consumedChar
elif consumedChar not in self._literalDelims:
consumed += consumedChar
else:
consumed = consumed[:-1] + consumedChar
else:
# Escape-Zeichen an letzter Position nicht konsumieren
break
prevChar = consumedChar
elif self._mode == LexerMode.LINE_COMMENT:
isTermination = ord(text) == WSCharCode.LINEBREAK
consumed = self._inputBuffer.consumeAll()
elif self._mode == LexerMode.BLOCK_COMMENT:
isTermination = text == self._blockCommentEnd
consumed = self._inputBuffer.consumeAll()
else:
raise Exception("Undefined lexer mode")
return consumed, isTermination
def _isWhiteSpace(self, ch):
if ch in self._literalDelims:
if self._currentLitDelim:
if ch == self._currentLitDelim:
self._currentLitDelim = ""
else:
self._currentLitDelim = ch
return False
elif self._currentLitDelim:
return False
else:
return ord(ch) in self._wsCharCodes
def _matchesCommentBegin(self, consumed, commentBegin):
tmp = commentBegin
for specialChar in ['*']:
tmp = tmp.replace(specialChar, '\\' + specialChar)
regex = r"\A%s.*\Z" % tmp
return bool(re.match(regex, consumed))
