Question

I am using ANTLR 3.1.3 to generate the parser. After importing the generated testParser, I found there is several errors like

try { dbg.enterDecision(2, decisionCanBacktrack[2]);

Description Resource Path Location Type
The method enterDecision(int) in the type DebugEventListener is not applicable for the arguments (int, boolean) testParser.java /ANTLRTest/src line 280 Java Problem

If I changed to dbg.enterDecision(2), then everything is fine.

The grammar is as follows,

grammar Test;  

options {output=AST;}

expr : mexpr (PLUS^ mexpr)* SEMI! ; 

mexpr : atom (STAR^ atom)* ;  
atom: INT ;  
//class csharpTestLexer extends Lexer;  
WS : (' ' | '\t' | '\n' | '\r') { $channel = HIDDEN; } ;  
LPAREN: '(' ;  
RPAREN: ')' ;  
STAR: '*' ;  
PLUS: '+' ;  
SEMI: ';' ; 

DIGIT : '0'..'9' ;  
INT : (DIGIT)+ ;  

I am using ANTLRWorks 1.4.3 to generate lexer and parser.

JDK 1.6

Any reason to this error?

Answer 1

It looks like you’ve generated a lexer and parser with an ANTLR version that is different than the one you added to Eclipse’s classpath.

If you generate a lexer and/or parser with ANTLRWorks 1.4.3 (which contains ANTLR 3.4), you should also add ANTLR 3.4 to your project’s build path in Eclipse and remove ANTLR 3.1.3 from it.

BTW, I get error for 2 + 2 * 3, do you know why? anything wrong with the above grammar.

That is because single digit numbers are being tokenized as DIGIT tokens. Either make DIGIT a fragment:

fragment DIGIT : '0'..'9' ;  
INT : (DIGIT)+ ;  

or remove it:

INT : '0'..'9'+ ;  

See: What does "fragment" mean in ANTLR?