Missing Logtalk 2.15.2 library files.

git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@826 b08c6af1-5177-4d33-ba66-4b1c6b8b522a

Logtalk/library/observer.lgt

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+
+:- category(observer).
+
+	:- info([
+		version is 1.0,
+		author is 'Paulo Moura',
+		date is 03/02/09,
+		comment is 'Smalltalk dependent protocol.']).
+
+	:- public(update/1).
+	:- mode(update(?nonvar), zero_or_one).
+	:- info(update/1,
+		[comment is 'Called when an observed object is updated.',
+		 argnames is ['Change']]).
+
+	update(_).
+
+:- end_category.

Logtalk/library/subject.lgt

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+
+:- category(subject).
+
+	:- info([
+		version is 1.0,
+		author is 'Paulo Moura',
+		date is 03/02/09,
+		comment is 'Smalltalk dependent handling predicates.']).
+
+	:- public(changed/0).
+	:- mode(changed, one).
+	:- info(changed/0,
+		[comment is 'Receiver changed in some way. Notify all dependents.']).
+
+	:- public(changed/1).
+	:- mode(changed(?nonvar), one).
+	:- info(changed/1,
+		[comment is 'Receiver changed as specified in the argument. Notify all dependents.',
+		 argnames is ['Change']]).
+
+	:- public(dependents/1).
+	:- mode(dependents(-list), one).
+	:- info(dependents/1,
+		[comment is 'Returns a list of all dependent objects.',
+		 argnames is ['Dependents']]).
+
+	:- private(dependent_/1).
+	:- dynamic(dependent_/1).
+	:- mode(dependent_(?object), zero_or_more).
+	:- info(dependent_/1,
+		[comment is 'Dependent object table.',
+		 argnames is ['Dependent']]).
+
+	:- public(addDependent/1).
+	:- mode(addDependent(@object), one).
+	:- info(addDependent/1,
+		[comment is 'Adds a new dependent object.',
+		 argnames is ['Dependent']]).
+
+	:- public(removeDependent/1).
+	:- mode(removeDependent(?object), zero_or_more).
+	:- info(removeDependent/1,
+		[comment is 'Removes a dependent object.',
+		 argnames is ['Dependent']]).
+
+	changed :-
+		self(Self),
+		forall(::dependent_(Dependent), Dependent::update(Self)).
+
+	changed(Change) :-
+		forall(::dependent_(Dependent), Dependent::update(Change)).
+
+	dependents(Dependents) :-
+		findall(Dependent, ::dependent_(Dependent), Dependents).
+
+	addDependent(Dependent) :-
+		::dependent_(Dependent) ->
+			true
+			;
+			::asserta(dependent_(Dependent)).
+
+	removeDependent(Dependent) :-
+		::retract(dependent_(Dependent)).
+
+:- end_category.