Wojciech~
Try pulling out the common left factor from your term expression:
term : factor (('*'|'/'|'*') term)?;
Matt
On Sat, Mar 19, 2011 at 12:18 PM, Wojciech Tomasz Cichon
<[email protected]> wrote:
> i’m struggling with this grammar for a few days now, and nothing really
> working,
> so i started from beginning and i have :
> grammar myGrammar;
>
> options {
> language = Java;
> k=1;
> }
>
> rule: term ;
>
> factor : '-'? NUMBER
> ;
>
> term : factor '*' term
> | factor '/' term
> | factor '%' term
> | factor;
>
>
>
> NUMBER : '0'..'9'+
> ;
> WS : ( ' '
> | '\t'
> | '\r'
> | '\n'
> ) {$channel=HIDDEN;}
> ;
>
>
> and i got errors:
> warning(200): /ANTLR_TEST/myGrammar.g:13:7: Decision can match input such as
> "'-'" using multiple alternatives: 1, 2, 3, 4
> As a result, alternative(s) 2,3,4 were disabled for that input
> |---> term : factor '*' term
>
> warning(200): /ANTLR_TEST/myGrammar.g:13:7: Decision can match input such as
> "NUMBER" using multiple alternatives: 1, 2, 3, 4
> As a result, alternative(s) 2,3,4 were disabled for that input
> |---> term : factor '*' term
>
> error(201): /ANTLR_TEST/myGrammar.g:13:7: The following alternatives can
> never be matched: 2,3,4
> |---> term : factor '*' term
>
> can anyone tell me what i’m doing wrong
> regards
>
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