List Search

[trica]

Hi everybody, I'm having a little problem with list seraching. I have to be able to find words in a word-puzzle.
I can't seem to solve the rule for searching a list of letters in another list.
Ex:
search([a,b,c],[[d,f,g],[e,a,b,c],N).
N=2.
I need to be able to find in what list it is, and I can't figure out how to go on after finding the first letter. Can anyone help me, please!
Thanx a lot.

 

[pimi]

Hello.
I cannot understand correctly what you want to do, but I guess...

*** program ***

samehead([], _).
samehead([X1|Xs], [X1|Ys]) :- samehead(Xs, Ys).

exist(X, Y) :- samehead(X, Y), !.
exist(X, [_|Y]) :- exist(X, Y).

search(X, [Y|_], 1) :- exist(X, Y), !.
search(X, [_|Ys], N) :- search(X, Ys, N2), N is N2 + 1.

*** sample ***

?- search([a, b, c], [[d, f, g], [e, a, b, c]], N).
N = 2 ;
no

?- search([a, b, c], [[d, f, g], [e, a, b]], N).
no

?- search([a, b, c], [[a, b, c, d, e], [a, b]], N).
N = 1 ;
no

?- search([a, b, c], [[a], , [a, b, c], [c]], N).
N = 3 ;
no