If I have struct_name(a, b, c, d, e)., how can I get the name of the struct? In this case, it would be struct_name.
Is there any specific command to do this or should I transform it in some way in a list (I tried and atom_chars doesn't work) and find save the characters until meeting ( ?
You can use the (=..)/2 predicate (this is an ISO-predicate, so it should work on (almost) all Prolog interpreters) that has on the left side a functor, and on the right side the name of the functor followed by its operands.
So:
?- struct_name(a, b, c, d, e) =.. L.
L = [struct_name, a, b, c, d, e].
You can thus obtain the name of the struct with:
get_name(A,N) :-
A =.. [N|_].
When you then call it with struct_name(a, b, c, d, e), it will give you:
?- get_name(struct_name(a, b, c, d, e),N).
N = struct_name.