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from antlr4 import *
class LexerAdaptor(Lexer):
"""
Track whether we are inside of a rule and whether it is lexical parser. _currentRuleType==Token.INVALID_TYPE
means that we are outside of a rule. At the first sign of a rule name reference and _currentRuleType==invalid, we
can assume that we are starting a parser rule. Similarly, seeing a token reference when not already in rule means
starting a token rule. The terminating ';' of a rule, flips this back to invalid type.
This is not perfect logic but works. For example, "grammar T;" means that we start and stop a lexical rule for
the "T;". Dangerous but works.
The whole point of this state information is to distinguish between [..arg actions..] and [charsets]. Char sets
can only occur in lexical rules and arg actions cannot occur.
"""
_currentRuleType = Token.INVALID_TYPE
def __init__(self, inp, output):
Lexer.__init__(self, inp, output)
def getCurrentRuleType(self):
return self._currentRuleType
def setCurrentRuleType(self, ruleType):
self._currentRuleType = ruleType
def handleBeginArgument(self):
if self.inLexerRule():
self.pushMode(self.LexerCharSet)
self.more()
else:
self.pushMode(self.Argument)
def handleEndArgument(self):
self.popMode()
if len(self._modeStack) > 0:
self._type = self.ARGUMENT_CONTENT
def handleEndAction(self):
self.popMode()
if len(self._modeStack) > 0:
self._type = self.ACTION_CONTENT
def emit(self):
if self._type == self.ID:
firstChar = self._input.getText(self._tokenStartCharIndex, self._tokenStartCharIndex)
if firstChar[0].isupper():
self._type = self.TOKEN_REF
else:
self._type = self.RULE_REF
if self._currentRuleType == Token.INVALID_TYPE: # if outside of rule def
self._currentRuleType = self._type # set to inside lexer or parser rule
elif self._type == self.SEMI: # exit rule def
self._currentRuleType = Token.INVALID_TYPE
return Lexer.emit(self)
def inLexerRule(self):
return self._currentRuleType == self.TOKEN_REF
def inParserRule(self): # not used, but added for clarity
return self._currentRuleType == self.RULE_REF
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