root/tlate/missing_value.hh

/*  This file is part of Alue, the multiprotocol Internet discussion daemon

    Copyright © 2009 Antti-Juhani Kaijanaho

    Alue is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    Alue 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 General Public License
    along with Alue.  If not, see <http://www.gnu.org/licenses/>.

 */

#ifndef GUARD_TLATE_MISSING_VALUE_HH
#define GUARD_TLATE_MISSING_VALUE_HH

#include "value.hh"

namespace tlate
{
        class missing_value : public value
        {
        public:
                typedef boost::shared_ptr<missing_value> ptr;
                typedef boost::shared_ptr<const missing_value> const_ptr;

                bool is_missing() const { return true; }
                void print(std::ostream &) const {}
        };
}


#endif /* GUARD_TLATE_MISSING_VALUE_HH */