:- object(set(_Type),
extends(set)).
:- info([
version is 1.01,
author is 'Paulo Moura',
date is 2006/4/25,
comment is 'Set predicates with elements constrained to a single type.']).
valid(Set) :-
nonvar(Set),
parameter(1, Type),
\+ \+ valid(Set, Type).
valid([], _) :-
!.
valid([Element], Type) :-
!,
Type::valid(Element).
valid([Element1, Element2| Set], Type) :-
Element1 @< Element2,
Type::valid(Element1),
Type::valid(Element2),
valid([Element2| Set], Type).
:- end_object.
