yap-6.3/Logtalk/examples/metapredicates/SCRIPT.txt

=================================================================
Logtalk - Object oriented extension to Prolog
Release 2.29.4

Copyright (c) 1998-2007 Paulo Moura.  All Rights Reserved.
=================================================================


% start by loading the necessary library support files (if not 
% already loaded):

| ?- logtalk_load(library(types_loader)).
...


% now you are ready for loading the example:

| ?- logtalk_load(metapredicates(loader)).
...


% note that "user" is a pseudo-object representing the Prolog database
% this implies that the integer comparisons are done using the standard
% Prolog built-in predicates

| ?- sort(user)::sort([3, 1, 4, 2, 9], Sorted).

call: partition([1,4,2,9],3,_358,_359)
exit: partition([1,4,2,9],3,[1,2],[4,9])
call: sort([1,2],_740)
call: partition([2],1,_967,_968)
exit: partition([2],1,[],[2])
call: sort([],_1300)
exit: sort([],[])
call: sort([2],_1539)
call: partition([],2,_1765,_1766)
exit: partition([],2,[],[])
call: sort([],_2093)
exit: sort([],[])
call: sort([],_2332)
exit: sort([],[])
exit: sort([2],[2])
exit: sort([1,2],[1,2])
call: sort([4,9],_2831)
call: partition([9],4,_3058,_3059)
exit: partition([9],4,[],[9])
call: sort([],_3391)
exit: sort([],[])
call: sort([9],_3630)
call: partition([],9,_3856,_3857)
exit: partition([],9,[],[])
call: sort([],_4184)
exit: sort([],[])
call: sort([],_4423)
exit: sort([],[])
exit: sort([9],[9])
exit: sort([4,9],[4,9])

Sorted = [1,2,3,4,9] ? 

yes


% call the meta-predicate apply/2 directly:

| ?- meta::test_this.

1, meta

yes


% send an apply/2 message to self:

| ?- desc::test_self.

2, desc

yes


% send an apply/2 message from another object:

| ?- test::test_obj.

3, test

yes