Re: permission error

[Cliff Bender]

After you told me, Ali, I dug deeper and found the source of the problem. It appears the example is using SWI-Prolog or similar and not gprolog, and clause/2 is built in and described as:

 

clause(?Head, ?Body)

Succeeds when Head can be unified with a clause head and Body with the corresponding clause body. Gives alternative clauses on backtracking. For facts Body is unified with the atom true. Normally clause/2 is used to find clause definitions for a predicate, but it can also be used to find clause heads for some body template.

does anyone know a site somewhere i can find examples and tutorials that use gprolog instead of swi or some other flavor? It would minimize my constant questions...

 

thanks,
Cliff

 

On 9/19/05, ED-DBALI AbdelAli <address@hidden> wrote:

Cliff Bender a écrit :
> ...
> clause_tree(G) :-
>    clause(G,Body),
>    clause_tree(Body).        /* grow branches */
> ...
> Does anybody have any idea? member is a built-in with gprolog (i know
> this because i tried to define one, and it says so) and i'm not calling
> clause/2, but clause_tree/2.

Hi,

You are calling clause/2 in de last clause : clause(G,Body) !!
That's why you got the error.

Ali.

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AbdelAli ED-DBALI, Maître de conférences (Informatique)
LIFO, Université d'Orléans
http://www.univ-orleans.fr/lifo/Membres/eddbali
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