Prolog Mystery

[Paulo J. Matos aka PDestroy]

Hi all,

I'm trying to do a predicate that given a list collects all
elements into another list that are not integer.
I've done the following:

np_collect([],X,X).
np_collect([Y|L], T, P) :- 
        \+ integer(Y),
        np_add(Y, T, R),
        np_collect(L, R, P).


For some strange reason it is not working...
We also have a restriction that we can't use -> for an unknown
reason.
Calling np_collect always fails and doing spy shows that the
predicate will never even test if Y is integer. I can't find
why. Can somebody please help... :)

Oh, and by the way...
        Hope you had a great Christmas and a Happy New Year...


Best regards,

-- 
Paulo J. Matos aka PDestroy : pocm(_at_)rnl.ist.utl.pt
Instituto Superior Tecnico - Lisbon    
Software & Computer Engineering - A.I.
 - > http://www.rnl.ist.utl.pt/~pocm 
 ---    
        Yes, God had a deadline...
                So, He wrote it all in Lisp!