root/tlate/var.cc

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

    Copyright © 2009, 2010 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/>.

 */

#include "std_value.hh"
#include "var.hh"

#include "../logger/logline.hh"

namespace tlate
{
        bool var::is_value_missing(overriding_structured_value::ptr env) {
                value::const_ptr rv = env->get(name);
                return !rv || rv->is_missing();
        }
        value::const_ptr var::eval_(overriding_structured_value::ptr env) {
                value::const_ptr rv = env->get(name);
                if (!rv || rv->is_missing())
                {
                        if (name == "_")
                                rv = std_value::singleton;
                        else
                        {
                                logger::logline ll;
                                ll << pos() 
                                   << ": access of a missing variable '"
                                   << name << "'";
                        }
                }
                return rv;
        }

}