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|
=================================================================
Logtalk - Object oriented extension to Prolog
Release 2.27.1
Copyright (c) 1998-2006 Paulo Moura. All Rights Reserved.
=================================================================
% start by loading the example:
| ?- logtalk_load(reflection(loader)).
...
% print the (public and protected) interface of each class:
| ?- (object, abstract_class, class)::print.
Object: object
interface:
new/1
delete/1
instances/1
metaclass/0
abstract_class/0
strict_instance/0
print/0
Object: abstract_class
interface:
new/1
delete/1
instances/1
metaclass/0
abstract_class/0
strict_instance/0
print/0
Object: class
interface:
new/1
delete/1
instances/1
metaclass/0
abstract_class/0
strict_instance/0
print/0
yes
% class is the metaclass of all classes:
| ?- class::instances(Instances), class::metaclass.
Instances = [class,abstract_class,object]
yes
% create an abstract_class, check it and print its interface:
| ?- abstract_class::new(ac), ac::abstract_class, ac::print.
Object: ac
interface:
metaclass/0
abstract_class/0
strict_instance/0
print/0
yes
% try to create an instance of the abstract class:
| ?- ac::new(i).
uncaught exception: error(existence_error(predicate_declaration,new(i)),ac::new(i),user)
% create a new instantiable class and print its interface:
| ?- class::new(c), c::print.
Object: c
interface:
new/1
delete/1
instances/1
metaclass/0
abstract_class/0
strict_instance/0
print/0
yes
% create an instance of the new class:
| ?- c::new(i), c::instances(Instances).
Instances = [i]
yes
% because c does not declare any predicates, its instances have no interface:
| ?- i::current_predicate(Predicate).
no
% create an instance of object, root of the inheritance graph, and print its interface:
| ?- object::new(j), j::print.
Object: j
interface:
strict_instance/0
print/0
yes
% delete the dynamic objects that we created:
| ?- c::delete(i), class::delete(c), abstract_class::delete(ac), object::delete(j).
yes
|
