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- #
- # 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.
- #/
- # A tuple: (ATN state, predicted alt, syntactic, semantic context).
- # The syntactic context is a graph-structured stack node whose
- # path(s) to the root is the rule invocation(s)
- # chain used to arrive at the state. The semantic context is
- # the tree of semantic predicates encountered before reaching
- # an ATN state.
- #/
- from io import StringIO
- from antlr4.PredictionContext import PredictionContext
- from antlr4.atn.ATNState import ATNState, DecisionState
- from antlr4.atn.LexerActionExecutor import LexerActionExecutor
- from antlr4.atn.SemanticContext import SemanticContext
- # need a forward declaration
- ATNConfig = None
- class ATNConfig(object):
- __slots__ = (
- 'state', 'alt', 'context', 'semanticContext', 'reachesIntoOuterContext',
- 'precedenceFilterSuppressed'
- )
- def __init__(self, state:ATNState=None, alt:int=None, context:PredictionContext=None, semantic:SemanticContext=None, config:ATNConfig=None):
- if config is not None:
- if state is None:
- state = config.state
- if alt is None:
- alt = config.alt
- if context is None:
- context = config.context
- if semantic is None:
- semantic = config.semanticContext
- if semantic is None:
- semantic = SemanticContext.NONE
- # The ATN state associated with this configuration#/
- self.state = state
- # What alt (or lexer rule) is predicted by this configuration#/
- self.alt = alt
- # The stack of invoking states leading to the rule/states associated
- # with this config. We track only those contexts pushed during
- # execution of the ATN simulator.
- self.context = context
- self.semanticContext = semantic
- # We cannot execute predicates dependent upon local context unless
- # we know for sure we are in the correct context. Because there is
- # no way to do this efficiently, we simply cannot evaluate
- # dependent predicates unless we are in the rule that initially
- # invokes the ATN simulator.
- #
- # closure() tracks the depth of how far we dip into the
- # outer context: depth > 0. Note that it may not be totally
- # accurate depth since I don't ever decrement. TODO: make it a boolean then
- self.reachesIntoOuterContext = 0 if config is None else config.reachesIntoOuterContext
- self.precedenceFilterSuppressed = False if config is None else config.precedenceFilterSuppressed
- # An ATN configuration is equal to another if both have
- # the same state, they predict the same alternative, and
- # syntactic/semantic contexts are the same.
- #/
- def __eq__(self, other):
- if self is other:
- return True
- elif not isinstance(other, ATNConfig):
- return False
- else:
- return self.state.stateNumber==other.state.stateNumber \
- and self.alt==other.alt \
- and ((self.context is other.context) or (self.context==other.context)) \
- and self.semanticContext==other.semanticContext \
- and self.precedenceFilterSuppressed==other.precedenceFilterSuppressed
- def __hash__(self):
- return hash((self.state.stateNumber, self.alt, self.context, self.semanticContext))
- def hashCodeForConfigSet(self):
- return hash((self.state.stateNumber, self.alt, hash(self.semanticContext)))
- def equalsForConfigSet(self, other):
- if self is other:
- return True
- elif not isinstance(other, ATNConfig):
- return False
- else:
- return self.state.stateNumber==other.state.stateNumber \
- and self.alt==other.alt \
- and self.semanticContext==other.semanticContext
- def __str__(self):
- with StringIO() as buf:
- buf.write('(')
- buf.write(str(self.state))
- buf.write(",")
- buf.write(str(self.alt))
- if self.context is not None:
- buf.write(",[")
- buf.write(str(self.context))
- buf.write("]")
- if self.semanticContext is not None and self.semanticContext is not SemanticContext.NONE:
- buf.write(",")
- buf.write(str(self.semanticContext))
- if self.reachesIntoOuterContext>0:
- buf.write(",up=")
- buf.write(str(self.reachesIntoOuterContext))
- buf.write(')')
- return buf.getvalue()
- # need a forward declaration
- LexerATNConfig = None
- class LexerATNConfig(ATNConfig):
- __slots__ = ('lexerActionExecutor', 'passedThroughNonGreedyDecision')
- def __init__(self, state:ATNState, alt:int=None, context:PredictionContext=None, semantic:SemanticContext=SemanticContext.NONE,
- lexerActionExecutor:LexerActionExecutor=None, config:LexerATNConfig=None):
- super().__init__(state=state, alt=alt, context=context, semantic=semantic, config=config)
- if config is not None:
- if lexerActionExecutor is None:
- lexerActionExecutor = config.lexerActionExecutor
- # This is the backing field for {@link #getLexerActionExecutor}.
- self.lexerActionExecutor = lexerActionExecutor
- self.passedThroughNonGreedyDecision = False if config is None else self.checkNonGreedyDecision(config, state)
- def __hash__(self):
- return hash((self.state.stateNumber, self.alt, self.context,
- self.semanticContext, self.passedThroughNonGreedyDecision,
- self.lexerActionExecutor))
- def __eq__(self, other):
- if self is other:
- return True
- elif not isinstance(other, LexerATNConfig):
- return False
- if self.passedThroughNonGreedyDecision != other.passedThroughNonGreedyDecision:
- return False
- if not(self.lexerActionExecutor == other.lexerActionExecutor):
- return False
- return super().__eq__(other)
- def hashCodeForConfigSet(self):
- return hash(self)
- def equalsForConfigSet(self, other):
- return self==other
- def checkNonGreedyDecision(self, source:LexerATNConfig, target:ATNState):
- return source.passedThroughNonGreedyDecision \
- or isinstance(target, DecisionState) and target.nonGreedy
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