Parser (ANTLR 4 Runtime 4.2.2 API)

java.lang.Object
- org.antlr.v4.runtime.Recognizer<Token,ParserATNSimulator>
- - org.antlr.v4.runtime.Parser

Direct Known Subclasses:

ParserInterpreter
```
public abstract class Parser
extends Recognizer<Token,ParserATNSimulator>
```
This is all the parsing support code essentially; most of it is error recovery stuff.

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

class Parser.TraceListener

static class Parser.TrimToSizeListener

Nested Classes
Modifier and Type	Class and Description
`class`	`Parser.TraceListener`
`static class`	`Parser.TrimToSizeListener`

Field Summary

Fields
Modifier and Type	Field and Description
`protected boolean`	`_buildParseTrees` Specifies whether or not the parser should construct a parse tree during the parsing process.
`protected ParserRuleContext`	`_ctx` The `ParserRuleContext` object for the currently executing rule.
`protected ANTLRErrorStrategy`	`_errHandler` The error handling strategy for the parser.
`protected TokenStream`	`_input` The input stream.
`protected List<ParseTreeListener>`	`_parseListeners` The list of `ParseTreeListener` listeners registered to receive events during the parse.
`protected IntegerStack`	`_precedenceStack`
`protected int`	`_syntaxErrors` The number of syntax errors reported during parsing.

Fields inherited from class org.antlr.v4.runtime.Recognizer
_interp, EOF

Constructor Summary

Constructors
Constructor and Description

Parser(TokenStream input)

Constructors
Constructor and Description
`Parser(TokenStream input)`

Method Summary

Methods
Modifier and Type	Method and Description
`protected void`	`addContextToParseTree()`
`void`	`addParseListener(ParseTreeListener listener)` Registers `listener` to receive events during the parsing process.
`ParseTreePattern`	`compileParseTreePattern(String pattern, int patternRuleIndex)` The preferred method of getting a tree pattern.
`ParseTreePattern`	`compileParseTreePattern(String pattern, int patternRuleIndex, Lexer lexer)` The same as `compileParseTreePattern(String, int)` but specify a `Lexer` rather than trying to deduce it from this parser.
`Token`	`consume()` Consume and return the current symbol.
`void`	`dumpDFA()` For debugging and other purposes.
`void`	`enterOuterAlt(ParserRuleContext localctx, int altNum)`
`void`	`enterRecursionRule(ParserRuleContext localctx, int ruleIndex)` Deprecated. Use `enterRecursionRule(ParserRuleContext, int, int, int)` instead.
`void`	`enterRecursionRule(ParserRuleContext localctx, int state, int ruleIndex, int precedence)`
`void`	`enterRule(ParserRuleContext localctx, int state, int ruleIndex)` Always called by generated parsers upon entry to a rule.
`void`	`exitRule()`
`ATN`	`getATNWithBypassAlts()` The ATN with bypass alternatives is expensive to create so we create it lazily.
`boolean`	`getBuildParseTree()` Gets whether or not a complete parse tree will be constructed while parsing.
`ParserRuleContext`	`getContext()`
`Token`	`getCurrentToken()` Match needs to return the current input symbol, which gets put into the label for the associated token ref; e.g., x=ID.
`List<String>`	`getDFAStrings()` For debugging and other purposes.
`ANTLRErrorStrategy`	`getErrorHandler()`
`IntervalSet`	`getExpectedTokens()` Computes the set of input symbols which could follow the current parser state and context, as given by `Recognizer.getState()` and `getContext()`, respectively.
`IntervalSet`	`getExpectedTokensWithinCurrentRule()`
`TokenStream`	`getInputStream()`
`ParserRuleContext`	`getInvokingContext(int ruleIndex)`
`int`	`getNumberOfSyntaxErrors()` Gets the number of syntax errors reported during parsing.
`List<ParseTreeListener>`	`getParseListeners()`
`int`	`getPrecedence()` Get the precedence level for the top-most precedence rule.
`ParserRuleContext`	`getRuleContext()`
`int`	`getRuleIndex(String ruleName)` Get a rule's index (i.e., `RULE_ruleName` field) or -1 if not found.
`List<String>`	`getRuleInvocationStack()` Return List<String> of the rule names in your parser instance leading up to a call to the current rule.
`List<String>`	`getRuleInvocationStack(RuleContext p)`
`String`	`getSourceName()`
`TokenFactory<?>`	`getTokenFactory()`
`TokenStream`	`getTokenStream()`
`boolean`	`getTrimParseTree()`
`boolean`	`inContext(String context)`
`boolean`	`isExpectedToken(int symbol)` Checks whether or not `symbol` can follow the current state in the ATN.
`Token`	`match(int ttype)` Match current input symbol against `ttype`.
`Token`	`matchWildcard()` Match current input symbol as a wildcard.
`void`	`notifyErrorListeners(String msg)`
`void`	`notifyErrorListeners(Token offendingToken, String msg, RecognitionException e)`
`boolean`	`precpred(RuleContext localctx, int precedence)`
`void`	`pushNewRecursionContext(ParserRuleContext localctx, int state, int ruleIndex)` Like `enterRule(org.antlr.v4.runtime.ParserRuleContext, int, int)` but for recursive rules.
`void`	`removeParseListener(ParseTreeListener listener)` Remove `listener` from the list of parse listeners.
`void`	`removeParseListeners()` Remove all parse listeners.
`void`	`reset()` reset the parser's state
`void`	`setBuildParseTree(boolean buildParseTrees)` Track the `ParserRuleContext` objects during the parse and hook them up using the `ParserRuleContext.children` list so that it forms a parse tree.
`void`	`setContext(ParserRuleContext ctx)`
`void`	`setErrorHandler(ANTLRErrorStrategy handler)`
`void`	`setInputStream(IntStream input)`
`void`	`setTokenFactory(TokenFactory<?> factory)` Tell our token source and error strategy about a new way to create tokens.
`void`	`setTokenStream(TokenStream input)` Set the token stream and reset the parser.
`void`	`setTrace(boolean trace)` During a parse is sometimes useful to listen in on the rule entry and exit events as well as token matches.
`void`	`setTrimParseTree(boolean trimParseTrees)` Trim the internal lists of the parse tree during parsing to conserve memory.
`protected void`	`triggerEnterRuleEvent()` Notify any parse listeners of an enter rule event.
`protected void`	`triggerExitRuleEvent()` Notify any parse listeners of an exit rule event.
`void`	`unrollRecursionContexts(ParserRuleContext _parentctx)`

Methods inherited from class org.antlr.v4.runtime.Recognizer
action, addErrorListener, getATN, getErrorHeader, getErrorListenerDispatch, getErrorListeners, getGrammarFileName, getInterpreter, getRuleIndexMap, getRuleNames, getSerializedATN, getState, getTokenErrorDisplay, getTokenNames, getTokenType, getTokenTypeMap, removeErrorListener, removeErrorListeners, sempred, setInterpreter, setState

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - _errHandler
```
@NotNull
protected ANTLRErrorStrategy _errHandler
```
    The error handling strategy for the parser. The default value is a new instance of DefaultErrorStrategy.
    
    See Also:
    getErrorHandler(), setErrorHandler(org.antlr.v4.runtime.ANTLRErrorStrategy)
  - _input
```
protected TokenStream _input
```
    The input stream.
    
    See Also:
    getInputStream(), setInputStream(org.antlr.v4.runtime.IntStream)
  - _precedenceStack
```
protected final IntegerStack _precedenceStack
```
  - _ctx
```
protected ParserRuleContext _ctx
```
    The ParserRuleContext object for the currently executing rule. This is always non-null during the parsing process.
  - _buildParseTrees
```
protected boolean _buildParseTrees
```
    Specifies whether or not the parser should construct a parse tree during the parsing process. The default value is true.
    
    See Also:
    getBuildParseTree(), setBuildParseTree(boolean)
  - _parseListeners
```
@Nullable
protected List<ParseTreeListener> _parseListeners
```
    The list of ParseTreeListener listeners registered to receive events during the parse.
    
    See Also:
    addParseListener(org.antlr.v4.runtime.tree.ParseTreeListener)
  - _syntaxErrors
```
protected int _syntaxErrors
```
    The number of syntax errors reported during parsing. This value is incremented each time notifyErrorListeners(java.lang.String) is called.
- Constructor Detail
  - Parser
```
public Parser(TokenStream input)
```
- Method Detail
  - reset
```
public void reset()
```
    reset the parser's state
  - match
```
@NotNull
public Token match(int ttype)
            throws RecognitionException
```
    Match current input symbol against ttype. If the symbol type matches, ANTLRErrorStrategy.reportMatch(org.antlr.v4.runtime.Parser) and consume() are called to complete the match process.
    If the symbol type does not match, ANTLRErrorStrategy.recoverInline(org.antlr.v4.runtime.Parser) is called on the current error strategy to attempt recovery. If getBuildParseTree() is true and the token index of the symbol returned by ANTLRErrorStrategy.recoverInline(org.antlr.v4.runtime.Parser) is -1, the symbol is added to the parse tree by calling ParserRuleContext.addErrorNode(org.antlr.v4.runtime.Token).
    
    Parameters:
    ttype - the token type to match
    
    Returns:
    the matched symbol
    
    Throws:
    
    RecognitionException - if the current input symbol did not match ttype and the error strategy could not recover from the mismatched symbol
  - matchWildcard
```
@NotNull
public Token matchWildcard()
                    throws RecognitionException
```
    Match current input symbol as a wildcard. If the symbol type matches (i.e. has a value greater than 0), ANTLRErrorStrategy.reportMatch(org.antlr.v4.runtime.Parser) and consume() are called to complete the match process.
    If the symbol type does not match, ANTLRErrorStrategy.recoverInline(org.antlr.v4.runtime.Parser) is called on the current error strategy to attempt recovery. If getBuildParseTree() is true and the token index of the symbol returned by ANTLRErrorStrategy.recoverInline(org.antlr.v4.runtime.Parser) is -1, the symbol is added to the parse tree by calling ParserRuleContext.addErrorNode(org.antlr.v4.runtime.Token).
    
    Returns:
    the matched symbol
    
    Throws:
    
    RecognitionException - if the current input symbol did not match a wildcard and the error strategy could not recover from the mismatched symbol
  - setBuildParseTree
```
public void setBuildParseTree(boolean buildParseTrees)
```
    Track the ParserRuleContext objects during the parse and hook them up using the ParserRuleContext.children list so that it forms a parse tree. The ParserRuleContext returned from the start rule represents the root of the parse tree.
    Note that if we are not building parse trees, rule contexts only point upwards. When a rule exits, it returns the context but that gets garbage collected if nobody holds a reference. It points upwards but nobody points at it.
    
    When we build parse trees, we are adding all of these contexts to ParserRuleContext.children list. Contexts are then not candidates for garbage collection.
  - getBuildParseTree
```
public boolean getBuildParseTree()
```
    Gets whether or not a complete parse tree will be constructed while parsing. This property is true for a newly constructed parser.
    
    Returns:
    true if a complete parse tree will be constructed while parsing, otherwise false
  - setTrimParseTree
```
public void setTrimParseTree(boolean trimParseTrees)
```
    Trim the internal lists of the parse tree during parsing to conserve memory. This property is set to false by default for a newly constructed parser.
    
    Parameters:
    trimParseTrees - true to trim the capacity of the ParserRuleContext.children list to its size after a rule is parsed.
  - getTrimParseTree
```
public boolean getTrimParseTree()
```
    Returns:
    true if the ParserRuleContext.children list is trimmed using the default Parser.TrimToSizeListener during the parse process.
  - getParseListeners
```
@NotNull
public List<ParseTreeListener> getParseListeners()
```
  - addParseListener
```
public void addParseListener(@NotNull
                    ParseTreeListener listener)
```
    Registers listener to receive events during the parsing process.
    To support output-preserving grammar transformations (including but not limited to left-recursion removal, automated left-factoring, and optimized code generation), calls to listener methods during the parse may differ substantially from calls made by ParseTreeWalker.DEFAULT used after the parse is complete. In particular, rule entry and exit events may occur in a different order during the parse than after the parser. In addition, calls to certain rule entry methods may be omitted.
    
    With the following specific exceptions, calls to listener events are deterministic, i.e. for identical input the calls to listener methods will be the same.
    - Alterations to the grammar used to generate code may change the behavior of the listener calls.
    - Alterations to the command line options passed to ANTLR 4 when generating the parser may change the behavior of the listener calls.
    - Changing the version of the ANTLR Tool used to generate the parser may change the behavior of the listener calls.
    Parameters:
    listener - the listener to add
    
    Throws:
    
    NullPointerException - if listener is null
  - removeParseListener
```
public void removeParseListener(ParseTreeListener listener)
```
    Remove listener from the list of parse listeners.
    If listener is null or has not been added as a parse listener, this method does nothing.
    
    Parameters:
    listener - the listener to remove
    See Also:
    addParseListener(org.antlr.v4.runtime.tree.ParseTreeListener)
  - removeParseListeners
```
public void removeParseListeners()
```
    Remove all parse listeners.
    
    See Also:
    addParseListener(org.antlr.v4.runtime.tree.ParseTreeListener)
  - triggerEnterRuleEvent
```
protected void triggerEnterRuleEvent()
```
    Notify any parse listeners of an enter rule event.
    
    See Also:
    addParseListener(org.antlr.v4.runtime.tree.ParseTreeListener)
  - triggerExitRuleEvent
```
protected void triggerExitRuleEvent()
```
    Notify any parse listeners of an exit rule event.
    
    See Also:
    addParseListener(org.antlr.v4.runtime.tree.ParseTreeListener)
  - getNumberOfSyntaxErrors
```
public int getNumberOfSyntaxErrors()
```
    Gets the number of syntax errors reported during parsing. This value is incremented each time notifyErrorListeners(java.lang.String) is called.
    
    See Also:
    notifyErrorListeners(java.lang.String)
  - getTokenFactory
```
public TokenFactory<?> getTokenFactory()
```
    Specified by:
    
    getTokenFactory in class Recognizer<Token,ParserATNSimulator>
  - setTokenFactory
```
public void setTokenFactory(TokenFactory<?> factory)
```
    Tell our token source and error strategy about a new way to create tokens.
    
    Specified by:
    
    setTokenFactory in class Recognizer<Token,ParserATNSimulator>
  - getATNWithBypassAlts
```
@NotNull
public ATN getATNWithBypassAlts()
```
    The ATN with bypass alternatives is expensive to create so we create it lazily.
    
    Throws:
    
    UnsupportedOperationException - if the current parser does not implement the Recognizer.getSerializedATN() method.
  - compileParseTreePattern
```
public ParseTreePattern compileParseTreePattern(String pattern,
                                       int patternRuleIndex)
```
    The preferred method of getting a tree pattern. For example, here's a sample use:
```
 ParseTree t = parser.expr();
 ParseTreePattern p = parser.compileParseTreePattern("<ID>+0", MyParser.RULE_expr);
 ParseTreeMatch m = p.match(t);
 String id = m.get("ID");
 
```
  - compileParseTreePattern
```
public ParseTreePattern compileParseTreePattern(String pattern,
                                       int patternRuleIndex,
                                       Lexer lexer)
```
    The same as compileParseTreePattern(String, int) but specify a Lexer rather than trying to deduce it from this parser.
  - getErrorHandler
```
@NotNull
public ANTLRErrorStrategy getErrorHandler()
```
  - setErrorHandler
```
public void setErrorHandler(@NotNull
                   ANTLRErrorStrategy handler)
```
  - getInputStream
```
public TokenStream getInputStream()
```
    Specified by:
    
    getInputStream in class Recognizer<Token,ParserATNSimulator>
  - setInputStream
```
public final void setInputStream(IntStream input)
```
    Specified by:
    
    setInputStream in class Recognizer<Token,ParserATNSimulator>
  - getTokenStream
```
public TokenStream getTokenStream()
```
  - setTokenStream
```
public void setTokenStream(TokenStream input)
```
    Set the token stream and reset the parser.
  - getCurrentToken
```
@NotNull
public Token getCurrentToken()
```
    Match needs to return the current input symbol, which gets put into the label for the associated token ref; e.g., x=ID.
  - notifyErrorListeners
```
public final void notifyErrorListeners(@NotNull
                        String msg)
```
  - notifyErrorListeners
```
public void notifyErrorListeners(@NotNull
                        Token offendingToken,
                        @NotNull
                        String msg,
                        @Nullable
                        RecognitionException e)
```
  - consume
```
public Token consume()
```
    Consume and return the current symbol.
    E.g., given the following input with A being the current lookahead symbol, this function moves the cursor to B and returns A.
```
  A B
  ^
 
```
    If the parser is not in error recovery mode, the consumed symbol is added to the parse tree using ParserRuleContext.addChild(Token), and ParseTreeListener.visitTerminal(org.antlr.v4.runtime.tree.TerminalNode) is called on any parse listeners. If the parser is in error recovery mode, the consumed symbol is added to the parse tree using ParserRuleContext.addErrorNode(Token), and ParseTreeListener.visitErrorNode(org.antlr.v4.runtime.tree.ErrorNode) is called on any parse listeners.
  - addContextToParseTree
```
protected void addContextToParseTree()
```
  - enterRule
```
public void enterRule(@NotNull
             ParserRuleContext localctx,
             int state,
             int ruleIndex)
```
    Always called by generated parsers upon entry to a rule. Access field _ctx get the current context.
  - exitRule
```
public void exitRule()
```
  - enterOuterAlt
```
public void enterOuterAlt(ParserRuleContext localctx,
                 int altNum)
```
  - getPrecedence
```
public final int getPrecedence()
```
    Get the precedence level for the top-most precedence rule.
    
    Returns:
    The precedence level for the top-most precedence rule, or -1 if the parser context is not nested within a precedence rule.
  - enterRecursionRule
```
@Deprecated
public void enterRecursionRule(ParserRuleContext localctx,
                                 int ruleIndex)
```
    Deprecated. Use enterRecursionRule(ParserRuleContext, int, int, int) instead.
  - enterRecursionRule
```
public void enterRecursionRule(ParserRuleContext localctx,
                      int state,
                      int ruleIndex,
                      int precedence)
```
  - pushNewRecursionContext
```
public void pushNewRecursionContext(ParserRuleContext localctx,
                           int state,
                           int ruleIndex)
```
    Like enterRule(org.antlr.v4.runtime.ParserRuleContext, int, int) but for recursive rules.
  - unrollRecursionContexts
```
public void unrollRecursionContexts(ParserRuleContext _parentctx)
```
  - getInvokingContext
```
public ParserRuleContext getInvokingContext(int ruleIndex)
```
  - getContext
```
public ParserRuleContext getContext()
```
  - setContext
```
public void setContext(ParserRuleContext ctx)
```
  - precpred
```
public boolean precpred(@Nullable
               RuleContext localctx,
               int precedence)
```
    Overrides:
    
    precpred in class Recognizer<Token,ParserATNSimulator>
  - inContext
```
public boolean inContext(String context)
```
  - isExpectedToken
```
public boolean isExpectedToken(int symbol)
```
    Checks whether or not symbol can follow the current state in the ATN. The behavior of this method is equivalent to the following, but is implemented such that the complete context-sensitive follow set does not need to be explicitly constructed.
```
 return getExpectedTokens().contains(symbol);
 
```
    Parameters:
    symbol - the symbol type to check
    
    Returns:
    true if symbol can follow the current state in the ATN, otherwise false.
  - getExpectedTokens
```
@NotNull
public IntervalSet getExpectedTokens()
```
    Computes the set of input symbols which could follow the current parser state and context, as given by Recognizer.getState() and getContext(), respectively.
    
    See Also:
    ATN.getExpectedTokens(int, RuleContext)
  - getExpectedTokensWithinCurrentRule
```
@NotNull
public IntervalSet getExpectedTokensWithinCurrentRule()
```
  - getRuleIndex
```
public int getRuleIndex(String ruleName)
```
    Get a rule's index (i.e., RULE_ruleName field) or -1 if not found.
  - getRuleContext
```
public ParserRuleContext getRuleContext()
```
  - getRuleInvocationStack
```
public List<String> getRuleInvocationStack()
```
    Return List<String> of the rule names in your parser instance leading up to a call to the current rule. You could override if you want more details such as the file/line info of where in the ATN a rule is invoked. This is very useful for error messages.
  - getRuleInvocationStack
```
public List<String> getRuleInvocationStack(RuleContext p)
```
  - getDFAStrings
```
public List<String> getDFAStrings()
```
    For debugging and other purposes.
  - dumpDFA
```
public void dumpDFA()
```
    For debugging and other purposes.
  - getSourceName
```
public String getSourceName()
```
  - setTrace
```
public void setTrace(boolean trace)
```
    During a parse is sometimes useful to listen in on the rule entry and exit events as well as token matches. This is for quick and dirty debugging.

Class Parser

Nested Class Summary

Field Summary

Fields inherited from class org.antlr.v4.runtime.Recognizer

Constructor Summary

Method Summary

Methods inherited from class org.antlr.v4.runtime.Recognizer

Methods inherited from class java.lang.Object

Field Detail

_errHandler

_input

_precedenceStack

_ctx

_buildParseTrees

_parseListeners

_syntaxErrors

Constructor Detail

Parser

Method Detail

reset

match

matchWildcard

setBuildParseTree

getBuildParseTree

setTrimParseTree

getTrimParseTree

getParseListeners

addParseListener

removeParseListener

removeParseListeners

triggerEnterRuleEvent

triggerExitRuleEvent

getNumberOfSyntaxErrors

getTokenFactory

setTokenFactory

getATNWithBypassAlts

compileParseTreePattern

compileParseTreePattern

getErrorHandler

setErrorHandler

getInputStream

setInputStream

getTokenStream

setTokenStream

getCurrentToken

notifyErrorListeners

notifyErrorListeners

consume

addContextToParseTree

enterRule

exitRule

enterOuterAlt

getPrecedence

enterRecursionRule

enterRecursionRule

pushNewRecursionContext

unrollRecursionContexts

getInvokingContext

getContext

setContext

precpred

inContext

isExpectedToken

getExpectedTokens

getExpectedTokensWithinCurrentRule

getRuleIndex

getRuleContext

getRuleInvocationStack

getRuleInvocationStack

getDFAStrings

dumpDFA

getSourceName

setTrace