[antlr-interest] ANTLR v3.0.1: Regression from ANTLR v2:?? left recusrsive grammar detected while it's not.

[Johannes Luber]

Francis ANDRE schrieb:
>  >>You have three section-s here - one for the rule, one for return and 
> one as label. ANTLR gets confused there. Rename at least the label and 
> the return parameter.
> Yes, I know.. it was done on purpose and works fine in ANTLR v2.. And as 
> the grammar has a more than 300 rules and 600 tokens, I would prefer to 
> let them as is
> Since ANTLR knows perfectly this is an assignment from a returned value 
> to a target language variable, IMHO, "section = " could be corrected as 
> a reference to the section variable and not an invocation of the 
> 'section' rule.

The "Since ANTLR knows perfectly this is an assignment from a returned
value to a target language variable" part can be debated, but I don't
know if a label can point to a return value anyway. Also I don't think
it is a good idea to allow the redefinition of names - people can be
easily confused.

Johannes
> Cheers
> 
> FA
> 
> Johannes Luber a écrit :
>>
>> Francis ANDRE schrieb:
>>> Hi ANTLR's
>>>
>>> Upon migration from ANTLR v2 to ANTLR v3 on the following snippet
>>>
>>> grammar Cobol;
>>> tokens {  DOT='DOT';    SECTION='SECTION';    IDENT='IDENT';}
>>> debut    :    section;
>>>
>>> section returns[PROCEDURE_SECTION section = null]
>>> @init {String s;}  :  section = sectionHeader DOT ;
>>
>> You have three section-s here - one for the rule, one for return and 
>> one as label. ANTLR gets confused there. Rename at least the label and 
>> the return parameter.
>>
>> Johannes
>>>
>>> sectionHeader returns[PROCEDURE_SECTION section = null]
>>>    :    IDENT SECTION    { section = $IDENT.getText(); };
>>>
>>>
>>> got this error: [17:39:46] error(211): Cobol.g:2941:6: [fatal] rule 
>>> section has non-LL(*) decision due to recursive rule invocations 
>>> reachable from alts 1,2.  Resolve by left-factoring or using 
>>> syntactic predicates or using backtrack=true option.
>>>
>>> IMHO,  in no way the 'section = ' is a left recursive invocation of 
>>> the section rule, but just the assignment if the result of 
>>> sectionHeader to the PROCEDURE_SECTION section.
>>>
>>> What's yours?
>>>
>>> FA
>>>
>>>
>>>
>>>
>>
>>
>>
> 
>