diff cpack/dml/lib/backend_json.pl @ 0:718306e29690 tip

commiting public release

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cpack/dml/lib/backend_json.pl	Tue Feb 09 21:05:06 2016 +0100
@@ -0,0 +1,53 @@
+/* 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(backend_json, 
+      [  python_json/3
+      ,  python_apply/3
+      ,  python_call/3
+      ,  python_call/4
+      ,  python_call/5
+      ]).
+
+:- use_module(library(http/json)).
+
+python_apply(Module:Function,Args,Result) :- !,
+   Input = _{ module:Module, function:Function, arguments:Args },
+   python_json('json_wrapper.py', Input, Output),
+   (  Output=error{value:Msg} -> throw(python_json_error(Msg,Module:Function))
+   ;  Output=ok{value:Result}
+   ).
+python_apply(Function,Args,Result) :- atom(Function),
+   python_apply('__builtin__':Function,Args,Result).
+
+python_call(ModFunc,A1,Result) :- python_apply(ModFunc,[A1],Result).
+python_call(ModFunc,A1,A2,Result) :- python_apply(ModFunc,[A1,A2],Result).
+python_call(ModFunc,A1,A2,A3,Result) :- python_apply(ModFunc,[A1,A2,A3],Result).
+
+python_json(Script,Input,Output) :-
+   setup_call_cleanup(
+      process_create( dml(python/Script),[],
+                      [ cwd(dml(python)), process(PID),
+                        stdin(pipe(ToScript)), stdout(pipe(FromScript))]),
+      call_cleanup(
+         (  call_cleanup(json_write_dict(ToScript,Input,[width(0),tag(tag)]), close(ToScript)),
+            json_read_dict(FromScript,Output,[tag(tag)])
+         ), exception(_), process_kill(PID)),
+      (close(FromScript), process_wait(PID,_))
+   ).
+