getting elements into a list

[djgloom]

Hello!

Could you help me with an advise: how to get elements into a list:

el(a).
el(b).
el(c).
...

so, that prolog answers:

? - list(L).
L = [a, b, c, ...]
No

Thank you in advance!

 

[surfbluedog]

You can achieve this using the inbuilt setof predicate like this:

el(a).
el(b).
el(c).

list(L):-
setof(X, el(X), L).

 

[djgloom]

Thanks a lot!
There is also equivalent builtin predicate findall(X, el(X), List)