Daniel@0: /* Part of DML (Digital Music Laboratory)
Daniel@0: 	Copyright 2014-2015 Samer Abdallah, University of London
Daniel@0: 	 
Daniel@0: 	This program is free software; you can redistribute it and/or
Daniel@0: 	modify it under the terms of the GNU General Public License
Daniel@0: 	as published by the Free Software Foundation; either version 2
Daniel@0: 	of the License, or (at your option) any later version.
Daniel@0: 
Daniel@0: 	This program is distributed in the hope that it will be useful,
Daniel@0: 	but WITHOUT ANY WARRANTY; without even the implied warranty of
Daniel@0: 	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
Daniel@0: 	GNU General Public License for more details.
Daniel@0: 
Daniel@0: 	You should have received a copy of the GNU General Public
Daniel@0: 	License along with this library; if not, write to the Free Software
Daniel@0: 	Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
Daniel@0: */
Daniel@0: 
Daniel@0: :- module(backend_json, 
Daniel@0:       [  python_json/3
Daniel@0:       ,  python_apply/3
Daniel@0:       ,  python_call/3
Daniel@0:       ,  python_call/4
Daniel@0:       ,  python_call/5
Daniel@0:       ]).
Daniel@0: 
Daniel@0: :- use_module(library(http/json)).
Daniel@0: 
Daniel@0: python_apply(Module:Function,Args,Result) :- !,
Daniel@0:    Input = _{ module:Module, function:Function, arguments:Args },
Daniel@0:    python_json('json_wrapper.py', Input, Output),
Daniel@0:    (  Output=error{value:Msg} -> throw(python_json_error(Msg,Module:Function))
Daniel@0:    ;  Output=ok{value:Result}
Daniel@0:    ).
Daniel@0: python_apply(Function,Args,Result) :- atom(Function),
Daniel@0:    python_apply('__builtin__':Function,Args,Result).
Daniel@0: 
Daniel@0: python_call(ModFunc,A1,Result) :- python_apply(ModFunc,[A1],Result).
Daniel@0: python_call(ModFunc,A1,A2,Result) :- python_apply(ModFunc,[A1,A2],Result).
Daniel@0: python_call(ModFunc,A1,A2,A3,Result) :- python_apply(ModFunc,[A1,A2,A3],Result).
Daniel@0: 
Daniel@0: python_json(Script,Input,Output) :-
Daniel@0:    setup_call_cleanup(
Daniel@0:       process_create( dml(python/Script),[],
Daniel@0:                       [ cwd(dml(python)), process(PID),
Daniel@0:                         stdin(pipe(ToScript)), stdout(pipe(FromScript))]),
Daniel@0:       call_cleanup(
Daniel@0:          (  call_cleanup(json_write_dict(ToScript,Input,[width(0),tag(tag)]), close(ToScript)),
Daniel@0:             json_read_dict(FromScript,Output,[tag(tag)])
Daniel@0:          ), exception(_), process_kill(PID)),
Daniel@0:       (close(FromScript), process_wait(PID,_))
Daniel@0:    ).
Daniel@0: