Re: glib, flex and bison

[John Cupitt ng-london org uk]

Peter Jay Salzman wrote:

> currently, my code is kind of ugly because i need to convert back and
> forth between standard and glib data types.  i'm using flex/bison to
> handle user input (i'm a flex/bison newbie).  basically, yytext is put
> into a union depending on the data type:
> 
>    %union
>    {
>       int  number;
>       char *string;
>       char character;
>    }
>    
>    %token <number>    NUMBER
>    %token <character> LETTER
>    %token <string>    WORD
>    %%
>    commands:
>       | commands command
>       ;
>    command:
>       TOK_SAVE WORD TOK_END      { SaveState($2); }
> 
> 
> it would be sweet beyond belief if i could somehow get bison/yacc to
> pass a GString rather than a char *.  this would save me alot of
> "conversion code".


Hi Peter, I think this is pretty easy. You just need to change your 
lexer as well. Something like (untested):

Parser:

----------
%union {
   ...
   GString *gstring;
   ...
}

%type <gstring> TK_IDENTIFIER

%%

command: 
TK_IDENTIFIER
   {
     Symbol *sym = symbol_new( $1 );
   }
----------

Lexer:

----------
[a-zA-Z_]* 
{
     yylval.gstring = g_string_new( yytext );
     return( TK_IDENTIFIER );
   }
----------

C:

----------
Symbol *
symbol_new( GString *name )
{
   .....
}
----------

John



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