From:	Richard Dawe <rich AT phekda DOT freeserve DOT co DOT uk>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Bison problem
Date:	Fri, 12 Jul 2002 23:45:04 +0100
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To:	djgpp AT delorie DOT com
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Hello.

maxam_80 wrote:
[snip]
> When I run Bison with standard data type, i.e int, no problem, I
> successfully compile. But when I compile it on string-oriented version
> of the same grammar, it fails.

What errors do you get?

[snip]
> /************************/
> /* Regles grammaticales ***********************************************/
> 
> %%
>    Entree :
>       /* Epsilon */     { ; }
>    |  Ligne Entree      { ; }
>    ;
> 
>    Ligne :
>       '\n'              { $$ = memset($$, 0, LG_LIGNE); }
>    |  Expression '\n'   { $$ = memset($$, 0, LG_LIGNE);
>                           printf("\t%s\n", $1);
>                         }
>    ;
> 
>    Expression :
>       Chiffre Expression   { $$ = strcat($$, $1);
>                              $$ = strcat($$, $2);
>                            }
>    |  Chiffre              { $$ = strcat($$, $1); }
>    ;
[snip]

I think you need an empty branch, so that Expression can terminate. Also, you
should use left-recursion, so that the memory usage is bounded. I think you
should try something like this:

Expression:
| Expression Chiffre { $$ = strcat($$, $2); }
;

Ah, but then your string will be constructed in the wrong order, I think.
Hmmm.

Regards,

-- 
Richard Dawe [ http://www.phekda.freeserve.co.uk/richdawe/ ]

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