/*
* opencog/atoms/flow/StreamValueOfLink.h
*
* Copyright (C) 2018, 2020 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_STREAM_VALUE_OF_LINK_H
#define _OPENCOG_STREAM_VALUE_OF_LINK_H
#include <opencog/atoms/flow/ValueOfLink.h>
namespace opencog
{
/** \addtogroup grp_atomspace
* @{
*/
/// The StreamValueOfLink returns a sample from the indicated stream.
/// It returns something of exactly the same base type as the stream,
/// effectively "freezing" the sample for all time.
///
class StreamValueOfLink : public ValueOfLink
{
public:
StreamValueOfLink(const HandleSeq&&, Type=STREAM_VALUE_OF_LINK);
StreamValueOfLink(const StreamValueOfLink&) = delete;
StreamValueOfLink& operator=(const StreamValueOfLink&) = delete;
// Return a pointer to a sample from the stream at the specified key.
virtual ValuePtr execute(AtomSpace*, bool);
static Handle factory(const Handle&);
};
LINK_PTR_DECL(StreamValueOfLink)
#define createStreamValueOfLink CREATE_DECL(StreamValueOfLink)
/** @}*/
}
#endif // _OPENCOG_STREAM_VALUE_OF_LINK_H