Message-ID:	<31970C85.5D8E@public1.guangzhou.gd.cn>
Date:	Mon, 13 May 1996 19:18:45 +0900
From:	Wang TianXing <gztxwang AT public1 DOT guangzhou DOT gd DOT cn>
Organization:	No Organization
MIME-Version:	1.0
To:	Nicholas Lynch <br516 AT FreeNet DOT Carleton DOT CA>
CC:	djgpp AT delorie DOT com
Subject:	Re: Bison, Yacc realted question
References:	<4n5dor$d1h AT freenet-news DOT carleton DOT ca>

Nicholas Lynch wrote:
> 
>  I've been trying to use Bison to create a script language for an RPG. I
> downloaded a little something about YACC off the net, it has helped a bit
> (I don't remember what the file was called exactly) but I still have a
> few questions.

Have you checked the examples in the bison info file?
 
>  I want to encorporate subroutines in my language. So, I thought that I might
> be able to do that like this:
> 
>  subroutine:      sub_name '(' arguments ')' '{' expressions '}'
>  ;
> 
>  But I am lost as to how I would define arguments and expressions. For
> arguments I need some way of passing muliple arguments, even no arguments,
> with ',' characters separating each.

arguments:
    /* no arguments */
    | one_or_more_arguments
;

one_or_more_arguments:
    argument
    | one_or_more_arguments ',' argument
;

argument:
    IDENTIFIER
;
 
>  Something else that is starting to bother me, would I have to do a sweep
> of my entire script looking for subroutines before I could run it? Because
> I'ld have to know what subroutines are defined, where they are and the
> arguments for each.

You definitely have to have its definition before to run a subroutine.  But
you can check all sub-routine calls to see if there is any undefined
one.  If there isn't, you can execute the parsed part of the script.

>  I think this may be a bit tricky for a beginner :)

Surely.

> << If there is a better newsgroup to take this to, please tell me, I feel
>    extremely off-topic >>

There's a comp.compilers newsgroup you can try. (I don't know its exact
purpose, though.)

Regards,
Wang TianXing

- Raw text -