155 lines
6.2 KiB
Python
155 lines
6.2 KiB
Python
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#
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# Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
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# Use of this file is governed by the BSD 3-clause license that
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# can be found in the LICENSE.txt file in the project root.
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#/
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# A tuple: (ATN state, predicted alt, syntactic, semantic context).
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# The syntactic context is a graph-structured stack node whose
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# path(s) to the root is the rule invocation(s)
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# chain used to arrive at the state. The semantic context is
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# the tree of semantic predicates encountered before reaching
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# an ATN state.
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#/
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from io import StringIO
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from antlr4.PredictionContext import PredictionContext
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from antlr4.atn.ATNState import ATNState, DecisionState
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from antlr4.atn.LexerActionExecutor import LexerActionExecutor
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from antlr4.atn.SemanticContext import SemanticContext
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# need a forward declaration
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ATNConfig = None
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class ATNConfig(object):
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def __init__(self, state:ATNState=None, alt:int=None, context:PredictionContext=None, semantic:SemanticContext=None, config:ATNConfig=None):
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if config is not None:
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if state is None:
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state = config.state
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if alt is None:
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alt = config.alt
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if context is None:
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context = config.context
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if semantic is None:
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semantic = config.semanticContext
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if semantic is None:
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semantic = SemanticContext.NONE
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# The ATN state associated with this configuration#/
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self.state = state
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# What alt (or lexer rule) is predicted by this configuration#/
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self.alt = alt
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# The stack of invoking states leading to the rule/states associated
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# with this config. We track only those contexts pushed during
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# execution of the ATN simulator.
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self.context = context
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self.semanticContext = semantic
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# We cannot execute predicates dependent upon local context unless
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# we know for sure we are in the correct context. Because there is
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# no way to do this efficiently, we simply cannot evaluate
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# dependent predicates unless we are in the rule that initially
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# invokes the ATN simulator.
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#
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# closure() tracks the depth of how far we dip into the
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# outer context: depth > 0. Note that it may not be totally
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# accurate depth since I don't ever decrement. TODO: make it a boolean then
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self.reachesIntoOuterContext = 0 if config is None else config.reachesIntoOuterContext
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self.precedenceFilterSuppressed = False if config is None else config.precedenceFilterSuppressed
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# An ATN configuration is equal to another if both have
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# the same state, they predict the same alternative, and
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# syntactic/semantic contexts are the same.
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#/
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def __eq__(self, other):
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if self is other:
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return True
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elif not isinstance(other, ATNConfig):
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return False
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else:
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return self.state.stateNumber==other.state.stateNumber \
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and self.alt==other.alt \
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and ((self.context is other.context) or (self.context==other.context)) \
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and self.semanticContext==other.semanticContext \
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and self.precedenceFilterSuppressed==other.precedenceFilterSuppressed
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def __hash__(self):
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return hash((self.state.stateNumber, self.alt, self.context, self.semanticContext))
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def hashCodeForConfigSet(self):
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return hash((self.state.stateNumber, self.alt, hash(self.semanticContext)))
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def equalsForConfigSet(self, other):
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if self is other:
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return True
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elif not isinstance(other, ATNConfig):
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return False
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else:
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return self.state.stateNumber==other.state.stateNumber \
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and self.alt==other.alt \
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and self.semanticContext==other.semanticContext
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def __str__(self):
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with StringIO() as buf:
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buf.write('(')
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buf.write(str(self.state))
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buf.write(",")
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buf.write(str(self.alt))
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if self.context is not None:
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buf.write(",[")
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buf.write(str(self.context))
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buf.write("]")
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if self.semanticContext is not None and self.semanticContext is not SemanticContext.NONE:
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buf.write(",")
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buf.write(str(self.semanticContext))
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if self.reachesIntoOuterContext>0:
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buf.write(",up=")
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buf.write(str(self.reachesIntoOuterContext))
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buf.write(')')
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return buf.getvalue()
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# need a forward declaration
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LexerATNConfig = None
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class LexerATNConfig(ATNConfig):
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def __init__(self, state:ATNState, alt:int=None, context:PredictionContext=None, semantic:SemanticContext=SemanticContext.NONE,
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lexerActionExecutor:LexerActionExecutor=None, config:LexerATNConfig=None):
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super().__init__(state=state, alt=alt, context=context, semantic=semantic, config=config)
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if config is not None:
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if lexerActionExecutor is None:
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lexerActionExecutor = config.lexerActionExecutor
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# This is the backing field for {@link #getLexerActionExecutor}.
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self.lexerActionExecutor = lexerActionExecutor
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self.passedThroughNonGreedyDecision = False if config is None else self.checkNonGreedyDecision(config, state)
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def __hash__(self):
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return hash((self.state.stateNumber, self.alt, self.context,
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self.semanticContext, self.passedThroughNonGreedyDecision,
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self.lexerActionExecutor))
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def __eq__(self, other):
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if self is other:
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return True
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elif not isinstance(other, LexerATNConfig):
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return False
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if self.passedThroughNonGreedyDecision != other.passedThroughNonGreedyDecision:
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return False
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if not(self.lexerActionExecutor == other.lexerActionExecutor):
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return False
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return super().__eq__(other)
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def hashCodeForConfigSet(self):
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return hash(self)
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def equalsForConfigSet(self, other):
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return self==other
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def checkNonGreedyDecision(self, source:LexerATNConfig, target:ATNState):
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return source.passedThroughNonGreedyDecision \
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or isinstance(target, DecisionState) and target.nonGreedy
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