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1

What is the best way of converting a Prolog list into a Prolog term (that is not a list), in terms of efficiency, and using existing built-in predicates as much as possible?

The interface and usage examples would be the following.

%% list_to_term(+List:list, +Functor:atom, -Term:term)
%
% Usage:
%
% ?- list_to_term([], myfunctor, Term).
% Term = myfunctor.
%
% ?- list_to_term([a, b, [c], D, 2], myfunctor, Term).
% Term = myfunctor(a, b, [c], D, 2).

I.e. the given list (which is actually a nested term) is flattened into a term with the given name.

I'm not saying that it makes sense to do this. (But if you think that it does, please provide a usecase in your answer.)

+4  A: 

You need to use the =.. operator, like so:

list_to_term(List, Functor, Term) :-
    Term =.. [Functor | List].
Pesto
You mean: Term =.. [Functor | List]?
Kaarel
@Kaarel: Oh, yeah. I misread your example. You are correct: in order to get the results you want, you need to use [Functor | List].
Pesto