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A collection of tests for ANTLR 4 Runtime libraries.
# [The "BSD license"]
# Copyright (c) 2013 Terence Parr
# Copyright (c) 2013 Sam Harwell
# Copyright (c) 2014 Eric Vergnaud
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# 3. The name of the author may not be used to endorse or promote products
# derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#/
from antlr4.IntervalSet import IntervalSet
from antlr4.Token import Token
class ATN(object):
INVALID_ALT_NUMBER = 0
# Used for runtime deserialization of ATNs from strings#/
def __init__(self, grammarType , maxTokenType ):
# The type of the ATN.
self.grammarType = grammarType
# The maximum value for any symbol recognized by a transition in the ATN.
self.maxTokenType = maxTokenType
self.states = []
# Each subrule/rule is a decision point and we must track them so we
# can go back later and build DFA predictors for them. This includes
# all the rules, subrules, optional blocks, ()+, ()* etc...
self.decisionToState = []
# Maps from rule index to starting state number.
self.ruleToStartState = []
# Maps from rule index to stop state number.
self.ruleToStopState = None
self.modeNameToStartState = dict()
# For lexer ATNs, this maps the rule index to the resulting token type.
# For parser ATNs, this maps the rule index to the generated bypass token
# type if the
# {@link ATNDeserializationOptions#isGenerateRuleBypassTransitions}
# deserialization option was specified; otherwise, this is {@code null}.
self.ruleToTokenType = None
# For lexer ATNs, this is an array of {@link LexerAction} objects which may
# be referenced by action transitions in the ATN.
self.lexerActions = None
self.modeToStartState = []
# Compute the set of valid tokens that can occur starting in state {@code s}.
# If {@code ctx} is null, the set of tokens will not include what can follow
# the rule surrounding {@code s}. In other words, the set will be
# restricted to tokens reachable staying within {@code s}'s rule.
def nextTokensInContext(self, s, ctx):
from antlr4.LL1Analyzer import LL1Analyzer
anal = LL1Analyzer(self)
return anal.LOOK(s, ctx=ctx)
# Compute the set of valid tokens that can occur starting in {@code s} and
# staying in same rule. {@link Token#EPSILON} is in set if we reach end of
# rule.
def nextTokensNoContext(self, s):
if s.nextTokenWithinRule is not None:
return s.nextTokenWithinRule
s.nextTokenWithinRule = self.nextTokensInContext(s, None)
s.nextTokenWithinRule.readonly = True
return s.nextTokenWithinRule
def nextTokens(self, s, ctx = None):
if ctx==None:
return self.nextTokensNoContext(s)
else:
return self.nextTokensInContext(s, ctx)
def addState(self, state):
if state is not None:
state.atn = self
state.stateNumber = len(self.states)
self.states.append(state)
def removeState(self, state):
self.states[state.stateNumber] = None # just free mem, don't shift states in list
def defineDecisionState(self, s):
self.decisionToState.append(s)
s.decision = len(self.decisionToState)-1
return s.decision
def getDecisionState(self, decision):
if len(self.decisionToState)==0:
return None
else:
return self.decisionToState[decision]
# Computes the set of input symbols which could follow ATN state number
# {@code stateNumber} in the specified full {@code context}. This method
# considers the complete parser context, but does not evaluate semantic
# predicates (i.e. all predicates encountered during the calculation are
# assumed true). If a path in the ATN exists from the starting state to the
# {@link RuleStopState} of the outermost context without matching any
# symbols, {@link Token#EOF} is added to the returned set.
#
# If {@code context} is {@code null}, it is treated as
# {@link ParserRuleContext#EMPTY}.
#
# @param stateNumber the ATN state number
# @param context the full parse context
# @return The set of potentially valid input symbols which could follow the
# specified state in the specified context.
# @throws IllegalArgumentException if the ATN does not contain a state with
# number {@code stateNumber}
#/
def getExpectedTokens(self, stateNumber, ctx ):
if stateNumber < 0 or stateNumber >= len(self.states):
raise Exception("Invalid state number.")
s = self.states[stateNumber]
following = self.nextTokens(s)
if Token.EPSILON not in following:
return following
expected = IntervalSet()
expected.addSet(following)
expected.removeOne(Token.EPSILON)
while (ctx != None and ctx.invokingState >= 0 and Token.EPSILON in following):
invokingState = self.states[ctx.invokingState]
rt = invokingState.transitions[0]
following = self.nextTokens(rt.followState)
expected.addSet(following)
expected.removeOne(Token.EPSILON)
ctx = ctx.parentCtx
if Token.EPSILON in following:
expected.addOne(Token.EOF)
return expected© 2015 - 2025 Weber Informatics LLC | Privacy Policy