CEDET

Hi Oliver,

 > What troubles me is that to me it seems that Wisent is not intended to
 > be used without Semantic. I downloaded the current Semantic beta
 > package. I have found no place to download Wisent separately and its
 > documentation is part of Semantic's documentation. But Semantic is a
 > rather big package that seems to do a lot more than just parsing. I
 > do not want to introduce too many dependencies.

Wisent is designed to be used without Semantic even if I wrote it to
be part of Semantic.  In the wisent directory there is a small
example in file wisent-expr.el of a such use.

However you will loose the handy facilities that Semantic provides to
write grammars in a Bison like format.  In core Wisent, grammars have
to be written in Lisp form.

 > As far as I can see (as I said, I have just started), I'd need only
 > wisent.el and---at compile time---wisent-comp.el to generate a parser
 > (I'd have to write my own lexer then?). Is that true? Will Wisent and
 > Semantic stay separate packages?

Yes what you need is the parser engine in wisent.el and the parser
generator in wisent-comp.el.  What you need too is the working library
from the cedet common package used by the parser generator to display
progress messages.  Of course, you have also to write a lexer suitable
to your parser.

 > Any chance that Wisent will become part of GNU Emacs in the future?

Let see ;-)

David

>>> Oliver Scholz <alkibiades@...> seems to think that:
  [ ... ]
>I want to write a parser for CSS 2, in order to write a CSS
>processor; i.e. not an addition to semantic to help me writing CSS,
>but a program that processes stylesheets and applies style
>information to buffer text. Right now I try to make up my mind
>whether I should use Wisent for this, or whether I should craft my
>parser by hand.

If CSS is much like html, then you could probably just use
xml-parse.el to do the work.  That would really cut down on the work
you need to do.

If not, Wisent is the best choice for writing an interpreter in Emacs
Lisp.

>What troubles me is that to me it seems that Wisent is not intended to
>be used without Semantic. I downloaded the current Semantic beta
>package. I have found no place to download Wisent separately and its
>documentation is part of Semantic's documentation. But Semantic is a
>rather big package that seems to do a lot more than just parsing. I
>do not want to introduce too many dependencies.

Most users do not care about the parser, only that they get the
services in semantic.  The cedet beta was put together as is to
simplify maintenance of all those packages for us, and to simplify
installation for users who used to need to install 3 to 4 different
tools just to satisfy a dependency from something like JDEE.

>As far as I can see (as I said, I have just started), I'd need only
>wisent.el and---at compile time---wisent-comp.el to generate a parser
>(I'd have to write my own lexer then?). Is that true? Will Wisent and
>Semantic stay separate packages?

You could also use semantic-lex.el to do your lexing.  It makes
writing lexers pretty easy, but any lisp function that returns a
token stream could work, including external programs that output
Emacs Lisp lexical token expressions.

It seems clear that the semantic tool, and likely the cedet
distribution is too big for what you want.  Do not forget that all of
CEDET and Semantic are covered by the GPL.  You are welcome to take
only the bits you need out, and make your own mini-distribution.  Care
would be needed to by those who install your tool not to install
conflicting versions of Semantic, however.

>Any chance that Wisent will become part of GNU Emacs in the future?
  [ ... ]

Richard Stallman has expressed interest in this.  As far as I know all
introductory paper work is available to the FSF to do this.  No one
has taken the time to do the integration of the 1.4.4 version of
Semantic.  It is likely it will happen when the CEDET distribution is
considered "stable" and released separately that such an integration
will occur.

Eric

-- 
          Eric Ludlam:                 zappo@..., eric@...
   Home: http://www.ludlam.net            Siege: http://www.siege-engine.com
Emacs: http://cedet.sourceforge.net               GNU: http://www.gnu.org

Thanks Eric, thanks David, for your replies.


"Eric M. Ludlam" <eric@...> writes:

[...]
> If CSS is much like html, then you could probably just use
> xml-parse.el to do the work.  That would really cut down on the work
> you need to do.

Unfortunately it isn't. The syntax seems rather to be inspired by C or
Pascal:

    BODY { 
      font-family: "Gill Sans", sans-serif;
      font-size: 12pt;
      margin: 3em; 
    }

> If not, Wisent is the best choice for writing an interpreter in Emacs
> Lisp.

Indeed! This is the very first time that I deal with a parser
generator and I find it great. I need to figure some details out yet,
but I played a bit with the grammar for CSS and I think this is The
Right Thing. Thanks a lot for this tool!

[...]
> You could also use semantic-lex.el to do your lexing.  It makes
> writing lexers pretty easy, but any lisp function that returns a
> token stream could work, including external programs that output
> Emacs Lisp lexical token expressions.

Too late. :-) I already wrote my lexer. 

[...]
> Richard Stallman has expressed interest in this.  As far as I know all
> introductory paper work is available to the FSF to do this.  No one
> has taken the time to do the integration of the 1.4.4 version of
> Semantic.  It is likely it will happen when the CEDET distribution is
> considered "stable" and released separately that such an integration
> will occur.
[...]

That's good news! Even for someone you knows a little bit Lisp like
me, it is nicer, if such a big package like Semantic is already
installed, set up and in sync with your Emacs. And if Wisent were part
of Emacs, I would not even have thought about not using it.

    Oliver
-- 
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