/*
* RewriteMixin.h
*
* Copyright (C) 2009, 2014 Linas Vepstas
*
* Author: Linas Vepstas <linasvepstas@gmail.com> January 2009
*
* 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_REWRITE_MIXIN_H
#define _OPENCOG_REWRITE_MIXIN_H
#include <vector>
#include <opencog/atomspace/AtomSpace.h>
#include <opencog/atoms/value/ContainerValue.h>
#include <opencog/query/PatternMatchCallback.h>
namespace opencog {
/**
* class RewriteMixin -- pattern matching callback for grounding implicands.
*
* This class is meant to be used with the pattern matcher. When the
* pattern matcher calls the callback, it will do so with a particular
* grounding of the search pattern. If this class is holding an ungrounded
* implicand, it will create a grounded version of the implicand. If
* the implicand is already grounded, then it's a no-op -- this class
* alone will *NOT* change its truth value. Use a derived class for
* this.
*
* The 'var_soln' argument in the callback contains the map from variables
* to ground terms. 'class Instantiator' is used to perform the actual
* grounding. A set of grounded expressions is created in 'result_set'.
* Note that the callback may be called many times reporting the same
* results. In that case the 'result_set' will contain unique solutions.
*/
class RewriteMixin :
public virtual PatternMatchCallback
{
protected:
AtomSpace* _as;
DECLARE_PE_MUTEX;
ValueSet _result_set;
ContainerValuePtr _result_queue;
void insert_result(ValuePtr);
PatternLinkPtr _plp;
HandleSeq _varseq;
HandleSeq _implicand;
std::map<Handle, ContainerValuePtr> _var_marginals;
std::map<Handle, ContainerValuePtr> _implicand_grnds;
void setup_marginals(void);
void set_plp(const PatternLinkPtr& plp)
{
_plp = plp;
_implicand = _plp->get_implicand();
}
void record_marginals(const GroundingMap&);
size_t _num_results;
public:
RewriteMixin(AtomSpace*, ContainerValuePtr&);
size_t max_results;
virtual void set_pattern(const Variables& vars,
const Pattern& pat)
{
_varseq = vars.varseq;
setup_marginals();
}
virtual bool propose_grounding(const GroundingMap &var_soln,
const GroundingMap &term_soln);
virtual bool start_search(void);
virtual bool search_finished(bool);
};
}; // namespace opencog
#endif // _OPENCOG_REWRITE_MIXIN_H