257 lines
8.0 KiB
Python
257 lines
8.0 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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# An ATN transition between any two ATN states. Subclasses define
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# atom, set, epsilon, action, predicate, rule transitions.
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#
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# <p>This is a one way link. It emanates from a state (usually via a list of
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# transitions) and has a target state.</p>
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#
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# <p>Since we never have to change the ATN transitions once we construct it,
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# we can fix these transitions as specific classes. The DFA transitions
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# on the other hand need to update the labels as it adds transitions to
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# the states. We'll use the term Edge for the DFA to distinguish them from
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# ATN transitions.</p>
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#
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from antlr4.IntervalSet import IntervalSet
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from antlr4.Token import Token
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# need forward declarations
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from antlr4.atn.SemanticContext import Predicate, PrecedencePredicate
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ATNState = None
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RuleStartState = None
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class Transition (object):
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# constants for serialization
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EPSILON = 1
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RANGE = 2
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RULE = 3
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PREDICATE = 4 # e.g., {isType(input.LT(1))}?
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ATOM = 5
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ACTION = 6
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SET = 7 # ~(A|B) or ~atom, wildcard, which convert to next 2
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NOT_SET = 8
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WILDCARD = 9
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PRECEDENCE = 10
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serializationNames = [
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"INVALID",
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"EPSILON",
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"RANGE",
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"RULE",
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"PREDICATE",
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"ATOM",
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"ACTION",
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"SET",
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"NOT_SET",
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"WILDCARD",
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"PRECEDENCE"
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]
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serializationTypes = dict()
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def __init__(self, target:ATNState):
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# The target of this transition.
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if target is None:
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raise Exception("target cannot be null.")
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self.target = target
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# Are we epsilon, action, sempred?
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self.isEpsilon = False
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self.label = None
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# TODO: make all transitions sets? no, should remove set edges
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class AtomTransition(Transition):
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def __init__(self, target:ATNState, label:int):
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super().__init__(target)
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self.label_ = label # The token type or character value; or, signifies special label.
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self.label = self.makeLabel()
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self.serializationType = self.ATOM
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def makeLabel(self):
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s = IntervalSet()
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s.addOne(self.label_)
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return s
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def matches( self, symbol:int, minVocabSymbol:int, maxVocabSymbol:int):
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return self.label_ == symbol
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def __str__(self):
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return str(self.label_)
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class RuleTransition(Transition):
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def __init__(self, ruleStart:RuleStartState, ruleIndex:int, precedence:int, followState:ATNState):
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super().__init__(ruleStart)
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self.ruleIndex = ruleIndex # ptr to the rule definition object for this rule ref
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self.precedence = precedence
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self.followState = followState # what node to begin computations following ref to rule
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self.serializationType = self.RULE
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self.isEpsilon = True
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def matches( self, symbol:int, minVocabSymbol:int, maxVocabSymbol:int):
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return False
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class EpsilonTransition(Transition):
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def __init__(self, target, outermostPrecedenceReturn=-1):
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super(EpsilonTransition, self).__init__(target)
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self.serializationType = self.EPSILON
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self.isEpsilon = True
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self.outermostPrecedenceReturn = outermostPrecedenceReturn
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def matches( self, symbol:int, minVocabSymbol:int, maxVocabSymbol:int):
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return False
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def __str__(self):
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return "epsilon"
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class RangeTransition(Transition):
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def __init__(self, target:ATNState, start:int, stop:int):
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super().__init__(target)
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self.serializationType = self.RANGE
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self.start = start
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self.stop = stop
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self.label = self.makeLabel()
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def makeLabel(self):
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s = IntervalSet()
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s.addRange(range(self.start, self.stop + 1))
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return s
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def matches( self, symbol:int, minVocabSymbol:int, maxVocabSymbol:int):
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return symbol >= self.start and symbol <= self.stop
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def __str__(self):
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return "'" + chr(self.start) + "'..'" + chr(self.stop) + "'"
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class AbstractPredicateTransition(Transition):
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def __init__(self, target:ATNState):
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super().__init__(target)
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class PredicateTransition(AbstractPredicateTransition):
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def __init__(self, target:ATNState, ruleIndex:int, predIndex:int, isCtxDependent:bool):
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super().__init__(target)
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self.serializationType = self.PREDICATE
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self.ruleIndex = ruleIndex
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self.predIndex = predIndex
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self.isCtxDependent = isCtxDependent # e.g., $i ref in pred
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self.isEpsilon = True
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def matches( self, symbol:int, minVocabSymbol:int, maxVocabSymbol:int):
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return False
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def getPredicate(self):
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return Predicate(self.ruleIndex, self.predIndex, self.isCtxDependent)
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def __str__(self):
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return "pred_" + str(self.ruleIndex) + ":" + str(self.predIndex)
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class ActionTransition(Transition):
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def __init__(self, target:ATNState, ruleIndex:int, actionIndex:int=-1, isCtxDependent:bool=False):
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super().__init__(target)
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self.serializationType = self.ACTION
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self.ruleIndex = ruleIndex
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self.actionIndex = actionIndex
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self.isCtxDependent = isCtxDependent # e.g., $i ref in pred
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self.isEpsilon = True
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def matches( self, symbol:int, minVocabSymbol:int, maxVocabSymbol:int):
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return False
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def __str__(self):
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return "action_"+self.ruleIndex+":"+self.actionIndex
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# A transition containing a set of values.
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class SetTransition(Transition):
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def __init__(self, target:ATNState, set:IntervalSet):
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super().__init__(target)
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self.serializationType = self.SET
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if set is not None:
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self.label = set
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else:
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self.label = IntervalSet()
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self.label.addRange(range(Token.INVALID_TYPE, Token.INVALID_TYPE + 1))
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def matches( self, symbol:int, minVocabSymbol:int, maxVocabSymbol:int):
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return symbol in self.label
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def __str__(self):
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return str(self.label)
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class NotSetTransition(SetTransition):
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def __init__(self, target:ATNState, set:IntervalSet):
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super().__init__(target, set)
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self.serializationType = self.NOT_SET
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def matches( self, symbol:int, minVocabSymbol:int, maxVocabSymbol:int):
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return symbol >= minVocabSymbol \
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and symbol <= maxVocabSymbol \
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and not super(type(self), self).matches(symbol, minVocabSymbol, maxVocabSymbol)
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def __str__(self):
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return '~' + super(type(self), self).__str__()
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class WildcardTransition(Transition):
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def __init__(self, target:ATNState):
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super().__init__(target)
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self.serializationType = self.WILDCARD
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def matches( self, symbol:int, minVocabSymbol:int, maxVocabSymbol:int):
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return symbol >= minVocabSymbol and symbol <= maxVocabSymbol
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def __str__(self):
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return "."
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class PrecedencePredicateTransition(AbstractPredicateTransition):
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def __init__(self, target:ATNState, precedence:int):
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super().__init__(target)
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self.serializationType = self.PRECEDENCE
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self.precedence = precedence
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self.isEpsilon = True
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def matches( self, symbol:int, minVocabSymbol:int, maxVocabSymbol:int):
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return False
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def getPredicate(self):
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return PrecedencePredicate(self.precedence)
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def __str__(self):
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return self.precedence + " >= _p"
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Transition.serializationTypes = {
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EpsilonTransition: Transition.EPSILON,
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RangeTransition: Transition.RANGE,
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RuleTransition: Transition.RULE,
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PredicateTransition: Transition.PREDICATE,
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AtomTransition: Transition.ATOM,
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ActionTransition: Transition.ACTION,
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SetTransition: Transition.SET,
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NotSetTransition: Transition.NOT_SET,
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WildcardTransition: Transition.WILDCARD,
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PrecedencePredicateTransition: Transition.PRECEDENCE
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}
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del ATNState
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del RuleStartState
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from antlr4.atn.ATNState import *
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