opencog-atomspace / opencog / atoms / reduct / BoolOpLink.cc

/*
 * opencog/atoms/reduct/BoolOpLink.cc
 *
 * Copyright (C) 2015,2018,2022 Linas Vepstas
 * All Rights Reserved
 * SPDX-License-Identifier: AGPL-3.0-or-later
 */

#include <opencog/atoms/atom_types/atom_types.h>
#include <opencog/atoms/base/ClassServer.h>
#include <opencog/atoms/value/BoolValue.h>
#include "BoolOpLink.h"

using namespace opencog;

BoolOpLink::BoolOpLink(const HandleSeq&& oset, Type t)
    : Link(std::move(oset), t)
{
	init();
}

void BoolOpLink::init(void)
{
	Type tscope = get_type();
	if (not nameserver().isA(tscope, BOOL_OP_LINK))
		throw InvalidParamException(TRACE_INFO, "Expecting a BoolOpLink");
}

// ============================================================

ValuePtr BoolOpLink::execute(AtomSpace* as, bool silent)
{
	size_t sz = size();
	if (0 == sz)
	{
		if (BOOL_OR_LINK == get_type()) return createBoolValue(false);
		if (BOOL_AND_LINK == get_type()) return createBoolValue(true);
		throw InvalidParamException(TRACE_INFO, "BoolNotLink expects an argument");
	}

	ValuePtr vp = _outgoing[0]->execute(as, silent);
	if (1 == sz and BOOL_NOT_LINK != get_type()) return vp;

	// XXX TODO we can relax this, and accept simple truth values, too.
	if (not nameserver().isA(vp->get_type(), BOOL_VALUE))
		throw InvalidParamException(TRACE_INFO, "Expecting a BoolBalue");

	BoolValuePtr bvp = BoolValueCast(vp);

	if (BOOL_NOT_LINK == get_type())
	{
		if (1 != sz)
			throw InvalidParamException(TRACE_INFO, "BoolNotLink expects one argument");
		return bool_not(bvp);
	}

	if (BOOL_AND_LINK == get_type())
	{
		ValuePtr result = vp;
		for (size_t i=1; i<sz; i++)
		{
			BoolValuePtr av = BoolValueCast(_outgoing[i]->execute(as, silent));
			result = bool_and(BoolValueCast(result), av);
		}
		return result;
	}

	if (BOOL_OR_LINK == get_type())
	{
		ValuePtr result = vp;
		for (size_t i=1; i<sz; i++)
		{
			BoolValuePtr av = BoolValueCast(_outgoing[i]->execute(as, silent));
			result = bool_or(BoolValueCast(result), av);
		}
		return result;
	}
	throw InvalidParamException(TRACE_INFO, "Unexpected BoolOpLink");
}

DEFINE_LINK_FACTORY(BoolOpLink, BOOL_OP_LINK);

// ============================================================