Cookie replacement function

[Jonathan Selander]

Hi, I'm trying to do a very trivial thing using flex/bison. I want to 
make a sort of cookie replacement function, that finds a pattern in a 
string and replaces it with something else.

The string to look for is in the format "%{text}" and later on perhaps 
"%{text:moretext}" ... I know this should be a very simple thing to do, 
but my brain doesn't seem to think the same. I've been reading some 
howtos and so on but I'm still not sure enough to know exactly what to 
do. My flex file looks like this:

------------------ main.lex ------------------

%{

#include "y.tab.h"

%}

%%

[[:alnum:]]+            yylval = yytext; return WORD;
^.*$                    yylval = yytext; return STRING;

----------------------------------------------

And the bison file like this:

------------------ main.y --------------------

%{

#include <stdio.h>

#define YYSTYPE char *

int yyparse(void);
int yylex(void);
int yyerror(const char *);

%}

%token STRING COOKIE WORD

%%

basic:
       | basic cookie
       ;

cookie: STRING
       |
       '%' '{' WORD '}'
       {
               printf("COOKIE: %s\n", $3);
       }
       ;

%%

int yyerror(const char *err)
{
       fprintf(stderr, "ERROR: %s\n", err);
       return 0;
}

int main()
{
       yyparse();
       return 0;
}

----------------------------------------------

The program is compiled with

bison -y -d main.y
flex main.lex
cc -W -Wall -O2 -g lex.yy.c y.tab.c  -o main -lfl

Obviously I want it to print "COOKIE: <name of found cookie>" when 
something simple as %{cookie} is typed. A simple hint on where I'm 
thinking wrong would be more than helpful. I suppose it's something very 
easy.

Regards,
Jonathan