Re: Multiple Parsers in the Same Program

[Patrick Bellasi]

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On Friday 03 September 2004 22:44, you wrote:
> > But when I do that... I'm able to compile but I just get a SEGMENTATION
>
> FAULT
>
> > when I run the parser.
> >
> > Anyone know what can be the problem?
>
> Probably an uninitialized pointer.  I suggest running your program in a
> debugger, such as the GNU debugger GDB.  Then you'll be able to pinpoint
> the exact spot.  Use `bt' to get a "backtrace", which will show you a
> listing of the current stack frames.  
Always done... But the info I'm getting are not useful for me.
The crash is inside yylex()...
... but the code seem to go in an infinite loop: bt show a great number of 
nested call of the same routine!

****************************************************************************
This is mi code
****************************************************************************
%{
#include <stdio.h>

int armlex () {
         return yylex();
}

int yyerror (char const *s) {
        fprintf (stderr, "%s\n", s);
        return 1;
}

%}

%token T_BEGIN
%token T_ADD
%token T_SUB
%token T_MOV
%token T_BX
%token T_END

%name-prefix="arm"

%%

prog: T_BEGIN stmts T_END
;
        
stmts:  stmt
        | stmts stmt
;
        
stmt: T_ADD {printf ("ARM[add]\n");}
        | T_SUB {printf ("ARM[sub]\n");}
        | T_MOV {printf ("ARM[mov]\n");}
        | T_BX  {printf ("Switching to THUMB mode...\n");}
;

%%

int main (int argc, char *argv[]) {

        extern FILE *yyin;
        ++argv; --argc;
        
        if (argc>0)
                yyin = fopen(argv[0], "r");
        else
                yyin=stdin;

        return armparse();

}

****************************************************************************

armlex is a wrapper for the parser to call the yylex of the scanner...
... but that code enter in an infinite loop!

A can't see the mistake!

> Emacs has a nice GDB-interface. 
I know thanks

> Laurence
Patrick
- -- 



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