DefineLink.h

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/*
 * opencog/atoms/DefineLink.h
 *
 * Copyright (C) 2015 Linas Vepstas
 * All Rights Reserved
 *
 * 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_DEFINE_LINK_H
#define _OPENCOG_DEFINE_LINK_H

#include <map>

#include <opencog/atomspace/AtomSpace.h>
#include <opencog/atomspace/Link.h>

namespace opencog
{
class DefineLink : public Link
{
protected:
    // Reference to the definition body (typically a node)
    Handle _alias;
    // Definition body that this link is defining.
    Handle _definition;

    void init(const HandleSeq&);
public:
    DefineLink(const HandleSeq&,
               TruthValuePtr tv = TruthValue::DEFAULT_TV(),
               AttentionValuePtr av = AttentionValue::DEFAULT_AV());

    DefineLink(const Handle& varcdecls, const Handle& body,
               TruthValuePtr tv = TruthValue::DEFAULT_TV(),
               AttentionValuePtr av = AttentionValue::DEFAULT_AV());

    DefineLink(Link &l);
    Handle get_alias(void) { return _alias; }
    Handle get_definition(void) { return _definition; }

    static Handle get_definition(const Handle& alias);
};

typedef std::shared_ptr<DefineLink> DefineLinkPtr;
static inline DefineLinkPtr DefineLinkCast(const Handle& h)
    { AtomPtr a(h); return std::dynamic_pointer_cast<DefineLink>(a); }
static inline DefineLinkPtr DefineLinkCast(AtomPtr a)
    { return std::dynamic_pointer_cast<DefineLink>(a); }

// XXX temporary hack ...
#define createDefineLink std::make_shared<DefineLink>

}

#endif // _OPENCOG_DEFINE_LINK_H