/*
* opencog/atoms/column/LinkColumn.h
*
* Copyright (C) 2015, 2022, 2025 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_LINK_COLUMN_H
#define _OPENCOG_LINK_COLUMN_H
#include <opencog/atoms/base/Link.h>
namespace opencog
{
/** \addtogroup grp_atomspace
* @{
*/
/// The LinkColumn returns a LinkValue vector of whatever it is
/// wrapping.
///
/// For example,
///
/// LinkColumn
/// Concept "a"
/// Concept "b"
///
/// will return a value vector of length two:
///
/// (LinkValue (Concept "a") (Concept "b"))
///
/// The intended use case is that this will be used with pattern
/// searches, to construct a list of columns.
class LinkColumn : public Link
{
protected:
ValuePtr do_execute(AtomSpace*, bool);
ValuePtr do_handle_loop(AtomSpace*, bool, const HandleSeq&);
public:
LinkColumn(const HandleSeq&&, Type = LINK_COLUMN);
LinkColumn(const LinkColumn&) = delete;
LinkColumn& operator=(const LinkColumn&) = delete;
virtual bool is_executable() const { return true; }
// Return a pointer to LinkValue holding a list of Values.
virtual ValuePtr execute(AtomSpace*, bool);
static Handle factory(const Handle&);
};
LINK_PTR_DECL(LinkColumn)
#define createLinkColumn CREATE_DECL(LinkColumn)
/** @}*/
}
#endif // _OPENCOG_LINK_COLUMN_H