size.hh

// This file is a part of Aurelia.
// Copyright (C) 2010  Valentin David
// Copyright (C) 2010  University of Bergen
//
// This program 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.
//
// 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 General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
#ifndef __SIZE_HH
# define __SIZE_HH

# include "../strategies.hh"

namespace aurelia {

  struct size_strategy {
    template <typename Pool>
    int operator()(const untyped_term<Pool>& t) const {
      typedef untyped_term<Pool> T;
      typedef untyped_constructor<Pool> C;

      try {
        if (t.constructor() != C::AS_EMPTY_LIST)
          throw failure();
        return 0;
      } catch (failure) {
        if (t.constructor() == C::AS_LIST) {
          return (*this)(t[1]) + 1;
        } else
          throw failure();
      }
    }
  };

  size_strategy size;

}

#endif