================================================================
Logtalk - Open source object-oriented logic programming language
Release 2.30.7
Copyright (c) 1998-2007 Paulo Moura. All Rights Reserved.
% start by loading the example and the required library files:
| ?- logtalk_load(shapes_ch(loader)).
...
% try some simple queries:
| ?- square::nsides(N).
! error(
existence_error(predicate_declaration, nsides(_)),
square::nsides(N),
user)
| ?- q1::(color(Color), side(Side), position(X, Y)).
Color = red
Side = 1
X = 0
Y = 0
yes
| ?- q2::(side(Side), area(Area), perimeter(Perimeter)).
Side = 3
Area = 9
Perimeter = 12
