stretching a list in prolog

Question

I want to be able to turn

this: [[[a],b],c]

into this: [a,b,c]

with a constantly changing lists, so far I've done this:

a([[[A],B],C]).
strechList(List,C):-
    List=[H,T],
    append(T,List1,C),
    strechList(H,List1).
strechList(A,A).

but it doesn't work.

`[H,T]` is a list of only two elements. I'm supposing you meant, `[H|T]` which is a list whose first element (*head*) is `H` and *tail list* is `T`. Your rule `strechList(A, A).` says that any list is the stretch of itself, which doesn't sound correct. — lurker, Mar 18 '15 at 23:43

score 1 · Accepted Answer · edited May 23 '17 at 12:06

1

That predicate is called 'flatten'. It's built-in if you're using SWI-Prolog. Also check this answer.

edited May 23 '17 at 12:06

Community

answered Mar 18 '15 at 22:24

vmg

Thank you i'm actually using SWi-prolog this is really helpful. :) – Dimitar Slavov Mar 19 '15 at 03:37

1 Answers1