/*
* opencog/atoms/sensory/TextStreamNode.h
*
* Copyright (C) 2024 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_TEXT_STREAM_NODE_H
#define _OPENCOG_TEXT_STREAM_NODE_H
#include <opencog/atoms/sensory/StreamNode.h>
namespace opencog
{
/** \addtogroup grp_atomspace
* @{
*/
/**
* TextStreamNode provides a virtual base class for objects that will
* be writing (utf8 or ascii) text. It consists of some utility methods
* that unpack, unwrap an assortment of Atoms, Values and TextStreams that
* might occur that have text flowing on them.
*
* Basically, it is a conversion shim that allows a loose assortment of
* almost anything to be streamed in, converting it into c++ strings
* that are easy to handle to the actual writer.
*
* This API is experimental.
*/
class TextStreamNode
: public StreamNode
{
protected:
ValuePtr string_to_type(std::string) const;
TextStreamNode(Type t, const std::string&&);
virtual void open(const ValuePtr&);
virtual ValuePtr read(void) const;
virtual std::string do_read(void) const;
virtual void do_write(const ValuePtr&);
// Derived classes need to implement a handler.
virtual void do_write(const std::string&) = 0;
virtual ValuePtr stream(void) const;
public:
virtual ~TextStreamNode();
};
NODE_PTR_DECL(TextStreamNode)
/** @}*/
} // namespace opencog
#endif // _OPENCOG_TEXT_STREAM_NODE_H