/*
* JsonEval.h
*
* A simple JSON shell-oriented evaluator
* Copyright (c) 2008, 2013, 2014, 2020, 2021 Linas Vepstas <linas@linas.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License v3 as
* published by the Free Software Foundation and including the exceptions
* at http://opencog.org/wiki/Licenses
*
* 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 Affero General Public License
* along with this program; if not, write to:
* Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef _OPENCOG_JSON_EVAL_H
#define _OPENCOG_JSON_EVAL_H
#include <mutex>
#include <string>
#include <opencog/atomspace/AtomSpace.h>
#include <opencog/eval/GenericEval.h>
/**
* The JsonEval class implements a very simple API for Javascript
* evaluation. It supports just enough commands to allow AtomSpaces
* and portions thereof to be easily transported across the network.
* It is used by the CogServer, and the atomspace-js network backend.
*/
namespace opencog {
/** \addtogroup grp_server
* @{
*/
class AtomSpace;
class JsonEval : public GenericEval
{
private:
AtomSpacePtr _atomspace;
// poll_result() is called in a different thread
// than eval_expr() and the result is that _answer
// can get clobbered. So force the reader to wait.
std::mutex _mtx;
std::string _answer;
JsonEval(const AtomSpacePtr&);
public:
virtual ~JsonEval();
virtual std::string get_name(void) const { return "JsonEval"; }
virtual void begin_eval(void);
virtual void eval_expr(const std::string&);
virtual std::string poll_result(void);
virtual void interrupt(void);
static JsonEval* get_evaluator(const AtomSpacePtr&);
};
/** @}*/
}
#endif // _OPENCOG_JSON_EVAL_H