ANTLR 4 Runtime (Optimized) 4.9.0 · org.antlr.v4.runtime.ParserInterpreter

Field Summary

Modifier and Type	Field and Description
protected final Deque<Tuple2<ParserRuleContext, Integer>>	_parentContextStack This stack corresponds to the _parentctx, _parentState pair of locals that would exist on call stack frames with a recursive descent parser; in the generated function for a left-recursive rule you'd see: private EContext e(int _p) throws RecognitionException { ParserRuleContext _parentctx = _ctx; // Pair.a int _parentState = getState(); // Pair.b ...
protected final ATN	atn
protected final String	grammarFileName
protected int	overrideDecision We need a map from (decision,inputIndex)->forced alt for computing ambiguous parse trees.
protected int	overrideDecisionAlt
protected int	overrideDecisionInputIndex
protected boolean	overrideDecisionReached
protected InterpreterRuleContext	overrideDecisionRoot What is the current context when we override a decisions?
protected final BitSet	pushRecursionContextStates This identifies StarLoopEntryState's that begin the (...)* precedence loops of left recursive rules.
protected InterpreterRuleContext	rootContext
protected final String[]	ruleNames
protected final String[]	tokenNames Deprecated
private final Vocabulary	vocabulary

Inherited from org.antlr.v4.runtime.Parser:: _buildParseTrees _ctx _errHandler _input _parseListeners _precedenceStack _syntaxErrors matchedEOF

Constructor Summary

Access	Constructor and Description
public	ParserInterpreter(ParserInterpreter The interpreter to copy old) A copy constructor that creates a new parser interpreter by reusing the fields of a previous interpreter.
public	ParserInterpreter(String grammarFileName, Collection<String> tokenNames, Collection<String> ruleNames, ATN atn, TokenStream input) Deprecated Use `ParserInterpreter(String, Vocabulary, Collection, ATN, TokenStream)` instead.
public	ParserInterpreter(String grammarFileName, Vocabulary vocabulary, Collection<String> ruleNames, ATN atn, TokenStream input)

Method Summary

Modifier and Type	Method and Description
public void	addDecisionOverride(int decision, int tokenIndex, int forcedAlt) Override this parser interpreters normal decision-making process at a particular decision and input token index.
protected InterpreterRuleContext	createInterpreterRuleContext(ParserRuleContext parent, int invokingStateNumber, int ruleIndex) Provide simple "factory" for InterpreterRuleContext's.
public void	enterRecursionRule(ParserRuleContext localctx, int state, int ruleIndex, int precedence) Overrides org.antlr.v4.runtime.Parser.enterRecursionRule.
public ATN	getATN() Overrides org.antlr.v4.runtime.Recognizer.getATN. Get the `ATN` used by the recognizer for prediction.
protected ATNState	getATNState()
public String	getGrammarFileName() Implements abstract org.antlr.v4.runtime.Recognizer.getGrammarFileName. For debugging and other purposes, might want the grammar name.
public InterpreterRuleContext	getOverrideDecisionRoot()
public InterpreterRuleContext	getRootContext() Return the root of the parse, which can be useful if the parser bails out.
public String[]	getRuleNames() Implements abstract org.antlr.v4.runtime.Recognizer.getRuleNames.
public String[]	getTokenNames() Implements abstract org.antlr.v4.runtime.Recognizer.getTokenNames. Deprecated Used to print out token names like ID during debugging and error reporting.
public Vocabulary	getVocabulary() Overrides org.antlr.v4.runtime.Recognizer.getVocabulary. Get the vocabulary used by the recognizer.
public ParserRuleContext	parse(int startRuleIndex) Begin parsing at startRuleIndex
protected void	recover(RecognitionException e) Rely on the error handler for this parser but, if no tokens are consumed to recover, add an error node.
protected Token	recoverInline()
public void	reset() Overrides org.antlr.v4.runtime.Parser.reset. reset the parser's state
protected int	visitDecisionState(DecisionState p) Method visitDecisionState() is called when the interpreter reaches a decision state (instance of DecisionState).
protected void	visitRuleStopState(ATNState p)
protected void	visitState(ATNState p)

Inherited from org.antlr.v4.runtime.Parser:: addContextToParseTree addParseListener compileParseTreePattern compileParseTreePattern consume createErrorNode createTerminalNode dumpDFA enterLeftFactoredRule enterOuterAlt enterRecursionRule enterRule exitRule getATNWithBypassAlts getBuildParseTree getContext getCurrentToken getDFAStrings getErrorHandler getErrorListenerDispatch getExpectedTokens getExpectedTokensWithinCurrentRule getInputStream getInvokingContext getNumberOfSyntaxErrors getParseInfo getParseListeners getPrecedence getRuleContext getRuleIndex getRuleInvocationStack getRuleInvocationStack getSourceName getTokenFactory getTrimParseTree inContext isExpectedToken isMatchedEOF isTrace match matchWildcard notifyErrorListeners notifyErrorListeners precpred pushNewRecursionContext removeParseListener removeParseListeners setBuildParseTree setContext setErrorHandler setInputStream setProfile setTrace setTrimParseTree triggerEnterRuleEvent triggerExitRuleEvent unrollRecursionContexts

Field Detail

_parentContextStack	back to summary
protected final Deque<Tuple2<ParserRuleContext, Integer>> _parentContextStack This stack corresponds to the _parentctx, _parentState pair of locals that would exist on call stack frames with a recursive descent parser; in the generated function for a left-recursive rule you'd see: private EContext e(int _p) throws RecognitionException { ParserRuleContext _parentctx = _ctx; // Pair.a int _parentState = getState(); // Pair.b ... } Those values are used to create new recursive rule invocation contexts associated with left operand of an alt like "expr '*' expr".

_parentContextStack

back to summary

protected final Deque<Tuple2<ParserRuleContext, Integer>> _parentContextStack

This stack corresponds to the _parentctx, _parentState pair of locals that would exist on call stack frames with a recursive descent parser; in the generated function for a left-recursive rule you'd see: private EContext e(int _p) throws RecognitionException { ParserRuleContext _parentctx = _ctx; // Pair.a int _parentState = getState(); // Pair.b ... } Those values are used to create new recursive rule invocation contexts associated with left operand of an alt like "expr '*' expr".

atn	back to summary
protected final ATN atn

grammarFileName	back to summary
protected final String grammarFileName

overrideDecision	back to summary
protected int overrideDecision We need a map from (decision,inputIndex)->forced alt for computing ambiguous parse trees. For now, we allow exactly one override.

overrideDecisionAlt	back to summary
protected int overrideDecisionAlt

overrideDecisionInputIndex	back to summary
protected int overrideDecisionInputIndex

overrideDecisionReached	back to summary
protected boolean overrideDecisionReached

overrideDecisionRoot	back to summary
protected InterpreterRuleContext overrideDecisionRoot What is the current context when we override a decisions? This tells us what the root of the parse tree is when using override for an ambiguity/lookahead check.

pushRecursionContextStates	back to summary
protected final BitSet pushRecursionContextStates This identifies StarLoopEntryState's that begin the (...)* precedence loops of left recursive rules.

rootContext	back to summary
protected InterpreterRuleContext rootContext

ruleNames	back to summary
protected final String[] ruleNames

tokenNames	back to summary
protected final String[] tokenNames Deprecated Annotations @Deprecated

vocabulary	back to summary
private final Vocabulary vocabulary Annotations @NotNull

Constructor Detail

ParserInterpreter	back to summary
public ParserInterpreter(ParserInterpreter old) A copy constructor that creates a new parser interpreter by reusing the fields of a previous interpreter. Parameters old:ParserInterpreter The interpreter to copy Since 4.5

ParserInterpreter

back to summary

public ParserInterpreter(ParserInterpreter old)

A copy constructor that creates a new parser interpreter by reusing the fields of a previous interpreter.

Parameters

old:ParserInterpreter: The interpreter to copy

Since

4.5

ParserInterpreter	back to summary
public ParserInterpreter(String grammarFileName, Collection<String> tokenNames, Collection<String> ruleNames, ATN atn, TokenStream input) Deprecated Use `ParserInterpreter(String, Vocabulary, Collection, ATN, TokenStream)` instead. Annotations @Deprecated

ParserInterpreter	back to summary
public ParserInterpreter(String grammarFileName, Vocabulary vocabulary, Collection<String> ruleNames, ATN atn, TokenStream input)

Method Detail

addDecisionOverride	back to summary
public void addDecisionOverride(int decision, int tokenIndex, int forcedAlt) Override this parser interpreters normal decision-making process at a particular decision and input token index. Instead of allowing the adaptive prediction mechanism to choose the first alternative within a block that leads to a successful parse, force it to take the alternative, 1..n for n alternatives. As an implementation limitation right now, you can only specify one override. This is sufficient to allow construction of different parse trees for ambiguous input. It means re-parsing the entire input in general because you're never sure where an ambiguous sequence would live in the various parse trees. For example, in one interpretation, an ambiguous input sequence would be matched completely in expression but in another it could match all the way back to the root. s : e '!'? ; e : ID \| ID '!' ; Here, x! can be matched as (s (e ID) !) or (s (e ID !)). In the first case, the ambiguous sequence is fully contained only by the root. In the second case, the ambiguous sequences fully contained within just e, as in: (e ID !). Rather than trying to optimize this and make some intelligent decisions for optimization purposes, I settled on just re-parsing the whole input and then using {link Trees#getRootOfSubtreeEnclosingRegion} to find the minimal subtree that contains the ambiguous sequence. I originally tried to record the call stack at the point the parser detected and ambiguity but left recursive rules create a parse tree stack that does not reflect the actual call stack. That impedance mismatch was enough to make it it challenging to restart the parser at a deeply nested rule invocation. Only parser interpreters can override decisions so as to avoid inserting override checking code in the critical ALL(*) prediction execution path. Since 4.5

addDecisionOverride

back to summary

public void addDecisionOverride(int decision, int tokenIndex, int forcedAlt)

Override this parser interpreters normal decision-making process at a particular decision and input token index. Instead of allowing the adaptive prediction mechanism to choose the first alternative within a block that leads to a successful parse, force it to take the alternative, 1..n for n alternatives. As an implementation limitation right now, you can only specify one override. This is sufficient to allow construction of different parse trees for ambiguous input. It means re-parsing the entire input in general because you're never sure where an ambiguous sequence would live in the various parse trees. For example, in one interpretation, an ambiguous input sequence would be matched completely in expression but in another it could match all the way back to the root. s : e '!'? ; e : ID | ID '!' ; Here, x! can be matched as (s (e ID) !) or (s (e ID !)). In the first case, the ambiguous sequence is fully contained only by the root. In the second case, the ambiguous sequences fully contained within just e, as in: (e ID !). Rather than trying to optimize this and make some intelligent decisions for optimization purposes, I settled on just re-parsing the whole input and then using {link Trees#getRootOfSubtreeEnclosingRegion} to find the minimal subtree that contains the ambiguous sequence. I originally tried to record the call stack at the point the parser detected and ambiguity but left recursive rules create a parse tree stack that does not reflect the actual call stack. That impedance mismatch was enough to make it it challenging to restart the parser at a deeply nested rule invocation. Only parser interpreters can override decisions so as to avoid inserting override checking code in the critical ALL(*) prediction execution path.

Since: 4.5

createInterpreterRuleContext	back to summary
protected InterpreterRuleContext createInterpreterRuleContext(ParserRuleContext parent, int invokingStateNumber, int ruleIndex) Provide simple "factory" for InterpreterRuleContext's. Since 4.5.1

createInterpreterRuleContext

back to summary

protected InterpreterRuleContext createInterpreterRuleContext(ParserRuleContext parent, int invokingStateNumber, int ruleIndex)

Provide simple "factory" for InterpreterRuleContext's.

Since: 4.5.1

enterRecursionRule	back to summary
public void enterRecursionRule(ParserRuleContext localctx, int state, int ruleIndex, int precedence) Overrides org.antlr.v4.runtime.Parser.enterRecursionRule. Annotations @Override

enterRecursionRule

back to summary

public void enterRecursionRule(ParserRuleContext localctx, int state, int ruleIndex, int precedence)

Overrides org.antlr.v4.runtime.Parser.enterRecursionRule.

Annotations

@Override

getATN back to summary

getATN	back to summary
public ATN getATN() Overrides org.antlr.v4.runtime.Recognizer.getATN. Doc from org.antlr.v4.runtime.Recognizer.getATN. Get the `ATN` used by the recognizer for prediction. Returns:ATN The `ATN` used by the recognizer for prediction. Annotations @Override

public ATN getATN()

Overrides org.antlr.v4.runtime.Recognizer.getATN.

Doc from org.antlr.v4.runtime.Recognizer.getATN.

Get the ATN used by the recognizer for prediction.

Returns:ATN

The ATN used by the recognizer for prediction.

Annotations

@Override

getATNState	back to summary
protected ATNState getATNState()

getGrammarFileName	back to summary
public String getGrammarFileName() Implements abstract org.antlr.v4.runtime.Recognizer.getGrammarFileName. Doc from org.antlr.v4.runtime.Recognizer.getGrammarFileName. For debugging and other purposes, might want the grammar name. Have ANTLR generate an implementation for this method. Annotations @Override

getGrammarFileName

back to summary

public String getGrammarFileName()

Implements abstract org.antlr.v4.runtime.Recognizer.getGrammarFileName.

Doc from org.antlr.v4.runtime.Recognizer.getGrammarFileName.

For debugging and other purposes, might want the grammar name. Have ANTLR generate an implementation for this method.

Annotations

@Override

getOverrideDecisionRoot	back to summary
public InterpreterRuleContext getOverrideDecisionRoot()

getRootContext	back to summary
public InterpreterRuleContext getRootContext() Return the root of the parse, which can be useful if the parser bails out. You still can access the top node. Note that, because of the way left recursive rules add children, it's possible that the root will not have any children if the start rule immediately called and left recursive rule that fails. Since 4.5.1

getRootContext

back to summary

public InterpreterRuleContext getRootContext()

Return the root of the parse, which can be useful if the parser bails out. You still can access the top node. Note that, because of the way left recursive rules add children, it's possible that the root will not have any children if the start rule immediately called and left recursive rule that fails.

Since: 4.5.1

getRuleNames	back to summary
public String[] getRuleNames() Implements abstract org.antlr.v4.runtime.Recognizer.getRuleNames. Annotations @Override

getRuleNames

back to summary

public String[] getRuleNames()

Implements abstract org.antlr.v4.runtime.Recognizer.getRuleNames.

Annotations

@Override

getTokenNames	back to summary
public String[] getTokenNames() Implements abstract org.antlr.v4.runtime.Recognizer.getTokenNames. Doc from org.antlr.v4.runtime.Recognizer.getTokenNames. Deprecated Used to print out token names like ID during debugging and error reporting. The generated parsers implement a method that overrides this to point to their String[] tokenNames. Annotations @Override @Deprecated

getTokenNames

back to summary

public String[] getTokenNames()

Implements abstract org.antlr.v4.runtime.Recognizer.getTokenNames.

Doc from org.antlr.v4.runtime.Recognizer.getTokenNames.

Deprecated

Used to print out token names like ID during debugging and error reporting. The generated parsers implement a method that overrides this to point to their String[] tokenNames.

Annotations

@Override
@Deprecated

getVocabulary back to summary

getVocabulary	back to summary
public Vocabulary getVocabulary() Overrides org.antlr.v4.runtime.Recognizer.getVocabulary. Doc from org.antlr.v4.runtime.Recognizer.getVocabulary. Get the vocabulary used by the recognizer. Returns:Vocabulary A `Vocabulary` instance providing information about the vocabulary used by the grammar. Annotations @Override

public Vocabulary getVocabulary()

Overrides org.antlr.v4.runtime.Recognizer.getVocabulary.

Doc from org.antlr.v4.runtime.Recognizer.getVocabulary.

Get the vocabulary used by the recognizer.

Returns:Vocabulary

A Vocabulary instance providing information about the vocabulary used by the grammar.

Annotations

@Override

parse	back to summary
public ParserRuleContext parse(int startRuleIndex) Begin parsing at startRuleIndex

recover	back to summary
protected void recover(RecognitionException e) Rely on the error handler for this parser but, if no tokens are consumed to recover, add an error node. Otherwise, nothing is seen in the parse tree.

recoverInline	back to summary
protected Token recoverInline()

reset	back to summary
public void reset() Overrides org.antlr.v4.runtime.Parser.reset. Doc from org.antlr.v4.runtime.Parser.reset. reset the parser's state Annotations @Override

reset

back to summary

public void reset()

Overrides org.antlr.v4.runtime.Parser.reset.

Doc from org.antlr.v4.runtime.Parser.reset.

reset the parser's state

Annotations

@Override

visitDecisionState	back to summary
protected int visitDecisionState(DecisionState p) Method visitDecisionState() is called when the interpreter reaches a decision state (instance of DecisionState). It gives an opportunity for subclasses to track interesting things.

visitRuleStopState	back to summary
protected void visitRuleStopState(ATNState p)

visitState	back to summary
protected void visitState(ATNState p)

public Class ParserInterpreter

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