Package org.antlr.runtime

Class Parser

java.lang.Object

org.antlr.runtime.BaseRecognizer

org.antlr.runtime.Parser

Direct Known Subclasses:

DebugParser

public class Parser
extends BaseRecognizer

A parser for TokenStreams. "parser grammars" result in a subclass of this.

Field Summary

Fields

Modifier and Type	Field	Description
TokenStream	input

Fields inherited from class org.antlr.runtime.BaseRecognizer

DEFAULT_TOKEN_CHANNEL, HIDDEN, INITIAL_FOLLOW_STACK_SIZE, MEMO_RULE_FAILED, MEMO_RULE_UNKNOWN, NEXT_TOKEN_RULE_NAME, state

Constructor Summary

Constructors

Constructor	Description
Parser(TokenStream input)
Parser(TokenStream input, RecognizerSharedState state)

Method Summary

Modifier and Type	Method	Description
protected Object	getCurrentInputSymbol(IntStream input)	Match needs to return the current input symbol, which gets put into the label for the associated token ref; e.g., x=ID.
protected Object	getMissingSymbol(IntStream input, RecognitionException e, int expectedTokenType, BitSet follow)	Conjure up a missing token during error recovery.
String	getSourceName()
TokenStream	getTokenStream()
void	reset()	reset the parser's state; subclasses must rewinds the input stream
void	setTokenStream(TokenStream input)	Set the token stream and reset the parser
void	traceIn(String ruleName, int ruleIndex)
void	traceOut(String ruleName, int ruleIndex)

Methods inherited from class org.antlr.runtime.BaseRecognizer

alreadyParsedRule, beginResync, combineFollows, computeContextSensitiveRuleFOLLOW, computeErrorRecoverySet, consumeUntil, consumeUntil, displayRecognitionError, emitErrorMessage, endResync, failed, getBacktrackingLevel, getErrorHeader, getErrorMessage, getGrammarFileName, getNumberOfSyntaxErrors, getRuleInvocationStack, getRuleInvocationStack, getRuleMemoization, getRuleMemoizationCacheSize, getTokenErrorDisplay, getTokenNames, match, matchAny, memoize, mismatchIsMissingToken, mismatchIsUnwantedToken, pushFollow, recover, recoverFromMismatchedSet, recoverFromMismatchedToken, reportError, setBacktrackingLevel, toStrings, traceIn, traceOut

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

input

public TokenStream input

Constructor Detail

Parser

public Parser(TokenStream input)

Parser

public Parser(TokenStream input,
              RecognizerSharedState state)

Method Detail

reset

public void reset()

Description copied from class: BaseRecognizer

reset the parser's state; subclasses must rewinds the input stream

Overrides:

reset in class BaseRecognizer

getCurrentInputSymbol

protected Object getCurrentInputSymbol(IntStream input)

Description copied from class: BaseRecognizer

Match needs to return the current input symbol, which gets put into the label for the associated token ref; e.g., x=ID. Token and tree parsers need to return different objects. Rather than test for input stream type or change the IntStream interface, I use a simple method to ask the recognizer to tell me what the current input symbol is. This is ignored for lexers.

Overrides:

getCurrentInputSymbol in class BaseRecognizer

getMissingSymbol

protected Object getMissingSymbol(IntStream input,
                                  RecognitionException e,
                                  int expectedTokenType,
                                  BitSet follow)

Description copied from class: BaseRecognizer

Conjure up a missing token during error recovery. The recognizer attempts to recover from single missing symbols. But, actions might refer to that missing symbol. For example, x=ID {f($x);}. The action clearly assumes that there has been an identifier matched previously and that $x points at that token. If that token is missing, but the next token in the stream is what we want we assume that this token is missing and we keep going. Because we have to return some token to replace the missing token, we have to conjure one up. This method gives the user control over the tokens returned for missing tokens. Mostly, you will want to create something special for identifier tokens. For literals such as '{' and ',', the default action in the parser or tree parser works. It simply creates a CommonToken of the appropriate type. The text will be the token. If you change what tokens must be created by the lexer, override this method to create the appropriate tokens.

Overrides:

getMissingSymbol in class BaseRecognizer

setTokenStream

public void setTokenStream(TokenStream input)

Set the token stream and reset the parser

getTokenStream

public TokenStream getTokenStream()

getSourceName

public String getSourceName()

Specified by:

getSourceName in class BaseRecognizer

traceIn

public void traceIn(String ruleName,
                    int ruleIndex)

traceOut

public void traceOut(String ruleName,
                     int ruleIndex)