Re: term_expansion/2 with DCG clauses

Hi!

To write a DCG **interpreter** instead of the term_expansion/2 compiler is a finger-easy students' job (cca. 10 lines of code). If you want to extend it (DCG--ABNF or anything else) - and if the definition is clear - then to write the appropriate interpreter is only a little bit more complicated.

yours: imre



On Tue, 13 Aug 2013 15:49:43 +0200
Wouter Beek <[email protected]> wrote:

> Hi Feliks,
> 
> My specific use case is that I want to generate DCGs based on ABNF (a
> variant of BNF). Most RFC standards define their syntax in ABNF and
> having them converted into DCGs seems convenient.
> 
> Here is my use of term_expansion/2. The conversion from ABNF to DCGs
> is done in rule//1.
> ~~~{.pl}
> system:term_expansion(ABNF, DCGs):-
>   ABNF =.. [:-,abnf(Atom),_],
>   atom_codes(Atom, Codes),
>   once(phrase(rule(DCGs), Codes)),
> abnf('repeat         =  1*DIGIT / (*DIGIT "*" *DIGIT)'):- true.
> ~~~
> 
> ---
> Cheers!,
> Wouter.
> 
> E-mail: [email protected]
> WWW: www.wouterbeek.com
> Tel.: 0647674624
> 
> 
> On Tue, Aug 13, 2013 at 3:15 PM, Feliks Kluzniak
> <[email protected]> wrote:
> > Hi,
> >
> > I find your question hard to understand.  Could you please give an example of what it is that you are after?
> >
> > Thanks,
> > -- Feliks
> >
> > On Aug 13, 2013, at 14:02, Wouter Beek <[email protected]> wrote:
> >
> >> Hi all,
> >>
> >> What would be the recommended way for replacing regular Prolog
> >> predicates with DCG rules? I would be nice if I could use the
> >> syntactic sugar / `-->`-notation in formulating the replacing rules.
> >>
> >> I was thinking of using term_expansion/2, but `ResultTerm =..
> >> [-->,Head,Body]` would not be correct since `-->` is not the name of
> >> the predicate.
> >>
> >> ---
> >> Cheers!,
> >> Wouter.
> >>
> >> E-mail: [email protected]
> >> WWW: www.wouterbeek.com
> >> Tel.: 0647674624
> >> _______________________________________________
> >> SWI-Prolog mailing list
> >> [email protected]
> >> https://lists.iai.uni-bonn.de/mailman/listinfo.cgi/swi-prolog
> >
> >
> _______________________________________________
> SWI-Prolog mailing list
> [email protected]
> https://lists.iai.uni-bonn.de/mailman/listinfo.cgi/swi-prolog


-- 
Kilián Imre <[email protected]>