Re: Strange behavior

[Laurent Deniau]

Hans Aberg wrote:
> At 12:35 +0100 2004/03/25, Laurent Deniau wrote:
>
> > I am using Bison 1.35 and 1.875 to parse the ISO C99 grammar and I found
> > a strange behavior on a very simple case:
>
>
> This is not really a Bison question, but a question of implementing a
> language using the LALR(1) parsing algorithm. As your language is
> well-known, it might be worthwhile asking around in the newsgroup
> comp.compilers, or in some of the C newsgroups to see if somebody already
> has done it. Some C compilers might already have it (GNU C?).

My question has nothing to do with the C99 grammar. It was just to fix 
the background, nothing more.

> Also, it is really a Help-Bison <address@hidden>, question, not a
> Bug-Bison question.
>
>
> > If I use the rule:
> >
> > direct_abstract_declarator
> >  : '(' abstract_declarator ')'
> >  | direct_abstract_declarator_opt '[' assignment_expression_opt ']'
> >  | direct_abstract_declarator_opt '[' '*' ']'
> >  | '(' parameter_type_list_opt ')'
> >  | direct_abstract_declarator '(' parameter_type_list_opt ')'
> >  ;
> >
> > I have only one shift/reduce conflict for all the grammar (the IF ELSE
> > one). But if I use the rule
>
>
> You can resolve the dangling else problem by setting token precedences on
> the THEN and ELSE tokens (using say %nonassoc).

This is what I use. But before dealing with precedence, I wanted to 
remove all the shift/reduce I had except the well know IF ELSE one.

 In C, one should probably
> set a precedence on ")" then.
>
> Tip: It is might be better to avoid the single quote ')' constructs, and
> instead use
> %token LP "("
> %token RP ")"
> ...
> %%
> ...>direct_abstract_declarator
>    : "(" abstract_declarator ")"

Using string here is quite dangerous since you replace the character 
ASCII value by a string literal address. No a good idea...

> Then your Flex grammart must have lines
> "("   { return RP; }
> etc.

Nothing about my question?

Thanks.

ld.