Logtalk 2.29.4 files.

git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1800 b08c6af1-5177-4d33-ba66-4b1c6b8b522a

Logtalk/examples/threads/buffer/NOTES.txt

@@ -0,0 +1,14 @@
+=================================================================
+Logtalk - Object oriented extension to Prolog
+Release 2.29.4
+
+Copyright (c) 1998-2007 Paulo Moura.  All Rights Reserved.
+=================================================================
+
+
+To load this example and for sample queries, please see the SCRIPT file.
+
+This folder contains a simple multi-threading example illustrating how 
+to use the Logtalk built-in predicates threaded_wait/1 and threaded_notify/1 
+for synchronizing threads writing to and reading from a buffer that can 
+only contain an item at the same time. 

Logtalk/examples/threads/buffer/SCRIPT.txt

@@ -0,0 +1,44 @@
+=================================================================
+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:
+
+| ?- logtalk_load(library(random_loader)).
+...
+
+
+% now you are ready for loading the example:
+
+| ?- logtalk_load(buffer(loader)).
+...
+
+
+% start the producer and the consumer, each one running in its own thread:
+
+| ?- threaded_ignore(producer::run(10)), threaded_ignore(consumer::run(10)).
+
+producer wrote item 0
+consumer read item 0
+producer wrote item 1
+consumer read item 1
+producer wrote item 2
+consumer read item 2
+producer wrote item 3
+consumer read item 3
+producer wrote item 4
+consumer read item 4
+producer wrote item 5
+consumer read item 5
+producer wrote item 6
+consumer read item 6
+producer wrote item 7
+consumer read item 7
+producer wrote item 8
+consumer read item 8
+producer wrote item 9
+consumer read item 9

Logtalk/examples/threads/buffer/buffer.lgt

@@ -0,0 +1,66 @@
+
+:- object(buffer).
+
+	:- threaded.
+
+	:- public([put/1, get/1]).
+
+	:- private(item/1).
+	:- dynamic(item/1).
+
+	put(N) :-
+		(	N > 0										% wait until the previous item is consumed
+		->	NP is N - 1, threaded_wait(consumed(NP))	% (except for the first item!) 
+		;	true
+		),
+		assertz(item(N)),
+		sender(Sender),
+		writeq(Sender), write(' wrote item '), write(N), nl,
+		threaded_notify(produced(N)).					% notify consumer that a new item is available
+
+	get(N) :-
+		threaded_wait(produced(N)),						% wait until an item is available
+		retract(item(N)),
+		sender(Sender),
+		writeq(Sender), write(' read item '), write(N), nl,
+		threaded_notify(consumed(N)).					% notify producer that the item was consumed
+
+:- end_object.
+
+
+:- object(producer).
+
+	:- public(run/1).
+
+	run(N) :-
+		run(0, N).
+
+	run(N, N) :- !.
+	run(M, N) :-
+		M < N,
+		random::random(1, 5, Random),	% simulate a variable time to 
+		thread_sleep(Random),			% produce a new item
+		buffer::put(M),
+		M2 is M + 1,
+		run(M2, N).
+
+:- end_object.
+
+
+:- object(consumer).
+
+	:- public(run/1).
+
+	run(N) :-
+		run(0, N).
+
+	run(N, N) :- !.
+	run(M, N) :-
+		M < N,
+		random::random(1, 5, Random),	% simulate a variable time
+		thread_sleep(Random),			% to consume an item
+		buffer::get(M),
+		M2 is M + 1,
+		run(M2, N).
+
+:- end_object.

Logtalk/examples/threads/buffer/loader.lgt

@@ -0,0 +1,13 @@
+
+:- initialization(
+	logtalk_load(
+		buffer)). 
+
+/*
+If you intend to use the FOP XSL:FO processor for generating PDF documenting
+files, comment the directive above and uncomment the directive below
+
+:- initialization(
+	logtalk_load(
+		buffer, [xmlsref(standalone)])).
+*/