:- object(list(_Type),
extends(list)).
:- info([
version is 1.01,
author is 'Paulo Moura',
date is 2006/4/25,
comment is 'List predicates with elements constrained to a single type.']).
valid(List) :-
nonvar(List),
parameter(1, Type),
\+ \+ valid(List, Type).
valid([], _).
valid([Value| List], Type) :-
Type::valid(Value),
valid(List, Type).
:- end_object.
