Re: A Beginner's (probably stupid) Question

[arief_mulya]

John wrote:
> > How do exactly one do interconnection between flex and
> > bison? I mean, how do the two interconnect with each other?
>
>
> In two ways:
>
> 1. Bison calls the function yylex(), which should return an integer
>    token. Flex's job is to generate yylex. Certain flex actions
>    (section 2 of flex input) should return the current token value. In
>    this way, flex actions communicate the current token value to
>    bison.
>
> 2. Bison provides the global variables yylval, and yylloc. Flex
>    actions may set the values of yylval and yylloc before returning a
>    token. In this way, flex actions communicate additional information
>    about the current token to bison.
>
> Notice that the communication is one-way, from flex to bison.  Rarely
> does it flow the other way.


Dear John,
Thanks for the enlightment.


I currently face a quite of heavy misguide here.

Let say I have this kind of line:
ABCDE=1231ABC,BCDEF=123414; <the ';' can also be a '!' a ',' 
or a space>

I want to take only the values after the '=' sign.

So in my first (rather stupid) tries I do this in my scanner:
---------------------------------------------------------
%%
.        /* skips */
[ \t]+$  /* garbage */

ABCDE=[0-9]*[A-Z]*/[,! ;]                {
                        yylval = (char *) strndup(
                                strchr(yytext, '=') + 1, 
yyleng - 1);
                        return ABCDE;
                        }
BCDEF=[0-9]*[A-Z]*/[,! ;]     {
                        yylval = (char *) strndup(
                                strchr(yytext, '=') + 1,	yyleng 
- 1);
                        return BCDEF;
                        }
----------------------------------------------------------


and in my parser I do this:
----------------------------------------------------------
%token ABCDE
%token BCDEF

%%
exp:      ABCDE {printf("%s\t", $1); free($1);}
        | BCDEF {printf("%s\t", $1); free($1);}
;

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

But it keep getting me blanks output, or syntax error.

I already do #define YYSTYPE char *
(which I learn, has also re-defined in the parser.h file 
manually, if it wants to be recognized in the scanner file)

Should I use my own variable(s)? to transfer data?

Any clues are very much appreciated.
Mean while I'm going to google on this matter. See if I can 
find some working examples.


Best Regards,
arief_mulya
--