BindLink.cc

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/*
 * BindLink.cc
 *
 * Copyright (C) 2009, 2014, 2015 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.
 */

#include <opencog/atomspace/ClassServer.h>
#include <opencog/atoms/core/FreeLink.h>

#include "BindLink.h"

using namespace opencog;

void BindLink::init(void)
{
    extract_variables(_outgoing);
    unbundle_clauses(_body);
    common_init();
    setup_components();
    _pat.redex_name = "anonymous BindLink";
}

BindLink::BindLink(const HandleSeq& hseq,
                   TruthValuePtr tv, AttentionValuePtr av)
    : PatternLink(BIND_LINK, hseq, tv, av)
{
    init();
}

BindLink::BindLink(Type t, const HandleSeq& hseq,
                   TruthValuePtr tv, AttentionValuePtr av)
    : PatternLink(t, hseq, tv, av)
{
    init();
}

BindLink::BindLink(Link &l)
    : PatternLink(l)
{
    Type t = l.getType();
    if (not classserver().isA(t, BIND_LINK))
    {
        const std::string& tname = classserver().getTypeName(t);
        throw InvalidParamException(TRACE_INFO,
            "Expecting a BindLink, got %s", tname.c_str());
    }

    init();
}

/* ================================================================= */
void BindLink::extract_variables(const HandleSeq& oset)
{
    size_t sz = oset.size();
    if (3 < sz)
        throw InvalidParamException(TRACE_INFO,
            "Expecting an outgoing set size of at most two, got %d", sz);

    // If the outgoing set size is one, then there are no variable
    // declarations; extract all free variables.
    if (2 == sz)
    {
        _body = oset[0];
        _implicand = oset[1];

        // Use the FreeLink class to find all the variables;
        // Use the VariableList class for build the Variables struct.
        FreeLink fl(oset[0]);
        VariableList vl(fl.get_vars());
        _varlist = vl.get_variables();
        return;
    }

    // If we are here, then the first outgoing set member should be
    // a variable declaration.
    _body = oset[1];
    _implicand = oset[2];

    // Initialize _varlist with the scoped variables
    init_scoped_variables(oset[0]);
}

/* ===================== END OF FILE ===================== */