comparison cpack/dml/lib/state.pl @ 0:718306e29690 tip

commiting public release

+/* Part of DML (Digital Music Laboratory)
+	Copyright 2014-2015 Samer Abdallah, University of London
+	 
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 2
+	of the License, or (at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public
+	License along with this library; if not, write to the Free Software
+	Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+:- module(state, [set_state/2, get_state/2, with_state/3, retract_state/1]).
+
+:- meta_predicate
+      with_state(:,+,0),
+      retract_state(:),
+      set_state(:,+),
+      get_state(:,-).
+
+:- use_module(insist).
+:- dynamic state/3.
+
+get_state(M:Key,Value) :- state(M,Key,Value).
+set_state(M:Key,Value) :-
+   retractall(state(M,Key,_)),
+   assert(state(M,Key,Value)).
+
+with_state(M:Key,Value,Goal) :-
+   insist(\+state(M,Key,_),state_exists(M:Key)),
+   setup_call_cleanup( 
+      assert(state(M,Key,Value)), Goal,
+      retract_state(M:Key)).
+
+retract_state(M:Key) :- retractall(state(M,Key,_)).
+
+