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Antlr3 Error Handling
March 26, 2007 * CommonTreeNodeStream didn't push correctly; couldn't handle very deeply nested trees. * Fixed bug Error Handling and Recovery All syntactic and semantic errors cause parser exceptions to Added CHANGES.txt runtime/Java/src/org/antlr/runtime/RecognizerSharedState.java src/org/antlr/test/TestCompositeGrammars.java src/org/antlr/tool/CompositeGrammar.java src/org/antlr/tool/CompositeGrammarTree.java 3.0.1 - August 13, 2007 [See target pages on the wiki for more information on the non-Java targets] August 7, 2007 * added escaping of Either case results (where supported by the language) in the creation of a try/catch block. Ack, hetero arg is on lots of templates. :( Moved ruleCleanUp() template into ASTTreeParser and ASTParser groups. * added noRewrite() template (to Java.stg) so we can insert code during rewrite mode this contact form
Hijacking Follow Sets as First Sets In order to have ANTLR compute the required recovery set for us, we first note that the set we want is not just the First EDIT First we have to clarify what is meant by symbol. More unit tests in TestAttributes. Generated Fri, 30 Sep 2016 12:30:43 GMT by s_hv972 (squid/3.5.20) https://theantlrguy.atlassian.net/wiki/display/ANTLR3/Error+reporting+and+recovery
Antlr4 Error Handling
May 18, 2007 * there were some dependencies with org.antlr.* that I removed from org.antlr.runtime.* 3.0 final - May 17, 2007 May 14, 2007 * Auto backtracking didn't work with ! The default exception handler will report an error, sync to the follow set of the rule, and return from that rule. It does not ignore any files you specify the commandline. Now says: error(202): CS.g:248:95: the decision cannot distinguish between alternative(s) 1,2 for input such as "DOT IDENTIFIER EOF" Also fixed bug where dangling states did not resolve to stop states. *
Sometimes we build trees in a grammar and some of the token boundaries are not set properly. This is useful not only for optional rule/token refs, but also during error recovery. TokenStreamException Indicates that something went wrong while generating a stream of tokens. Fixes ANTLR-195.
Also Delete special case of replace (text==null): D.i-j.u D.x-y.v | boundaries overlap => combine to max(min)..max(right) December 12, 2010 * Send couldBacktrack now to enterDecision in debug protocol December 4, 2010 The exceptionType is the exception (or class of exceptions) to catch, and the exceptionVariable is the variable name of the caught exception, so that the action can process the exception if That way, the parser doesn't have to deal with lexical errors and ask for another token. http://stackoverflow.com/questions/2003705/seeking-very-simple-antlr-error-handling-example-when-generating-c-code Note that IO exceptions are passed back as TokenStreamIOException's regardless of this option.
Very useful for predicating tree grammar productions according to context (their parent list). If ANTLR can determine, using the Follow sets, that by skipping a token, it would see valid syntax, then it will consume the spurious token, report the extra token, but will If the lookahead predicts no alternative of a production in either the parser or lexer, then a NoViableAltException is thrown. codegen/templates/Java/ASTTreeParser.stg The templates needed to build trees with auto construction during tree parsing.
Antlr Error Listener Example
Thanks to Chris DiGiano. * added new buffered on-demand streams: BufferedTokenStream. Get More Information Note that the calling code will not report an error if this method returns successfully. Antlr4 Error Handling Parameters:recognizer - the parser instance reportError voidreportError(Parserrecognizer, RecognitionExceptione) Report any kind of RecognitionException. Method Detail reset voidreset(Parserrecognizer) Reset the error handler state for the specified recognizer.
ANTLR's default exception handling is good to get something working, but you will have more control over error-reporting and resynchronization if you write your own exception handlers. http://dis-lb.net/error-handling/asp-error-handling.php Can you find me? But, we need to gate actions when backtracking option is set even if no decision is generated to support filtering of trees. Basically an error in the classMember will abandon the parse of the class definition.
Further it may terminate sooner just due to reduced closure recursion. * Moved FIRST/FOLLOW computations to a separate class LL1Analyzer to tidy up. * ANTLR lexer allowed octal escapes, but they Token types are 32-bit clean using -1 not 0x0000FFFF as -1 so it should be okay. Was calling BaseRecognizer version not subclass. navigate here Note that the '@' exception specification of PCCTS 1.33 does not apply to ANTLR.
Parser rules throw RecognitionException and TokenStreamException. June 25, 2008 * List labels in tree construction didn't always track the tree; sometimes had a rule result structure. Decision is non-LL(*) even if some pieces are LL(*).
Wasn't building decisions properly for subrules in syntactic predicates.
Added methods for conjuring up missing symbols: getMissingSymbol(). * refactored BaseRecognizer error handling routines * Single token error recovery was not properly taking into consideration EOF. * ANTLR no longer tries Just an ASTDbg.stg change. It builds a completely new tree from old tree; i.e., you get two trees in memory. We could of course // use a custom action instead if there were special rules about // recovery for this language - here we just don't want to drop out //
December 29, 2007 * Fixed ANTLR-206.