Re: Disjunction in phrase/[2,3]

On 07/28/2013 10:29 AM, Wouter Beek wrote:
> Hi all,
> 
> I get the following warning for the use of disjunction in meta-DCG rules:
> ~~~
> Warning: The predicates below are not defined. If these are defined
> Warning: at runtime using assert/1, use :- dynamic Name/Arity.
> Warning:
> Warning: test:;/4, which is referenced by
> Warning:        c:/prolog/webqr/test.pl:6:5: 1-st clause of test:a/2
> ~~~
> 
> Am I doing something wrong or is the missing predicates check too
> restrictive?
> 
> Sample code:
> ~~~{.pl}
> a -->  x((b ; c)).
> b --> [98].
> c --> [99].
> :- meta_predicate(x(2,?,?)).

Works with this declaration.  DCG bodies are are bit more complicated
than just '2', so you must tell the system.

:- meta_predicate(x(//,?,?)).

	Cheers --- Jan

> x(DCG, A, B):- phrase(DCG, A, B).
> ~~~
> 
> ---
> Cheers,
> Wouter Beek.
> 
> E-mail: [email protected]
> WWW: www.wouterbeek.com
> Tel.: 0647674624
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