const_map.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 __CONST_MAP_HH
# define __CONST_MAP_HH

# include "../strategies.hh"
# include <bitset>

namespace aurelia {

  template <typename S>
  struct const_map_strategy {
    S s;
    const_map_strategy(const S& s): s(s) {
    }

    template <int N>
    std::bitset<N> operator()(const std::bitset<N>& t) const {
      for (unsigned i = 0; i < N; ++i) {
      s(t[i]);
      }
      return t;
    }

    template <typename T>
    T operator()(const T& t) const {
      for (typename T::const_iterator i = t.begin(); i != t.end(); ++i)
        s(*i);
      return t;
    }

    template <typename Pool>
    untyped_term<Pool> 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 t;
      } catch (failure) {
        if (t.constructor() == C::AS_LIST) {
          s(t[0]);
          (*this)(t[1]);
          return t;
        } else
          throw failure();
      }
    }
  };

  template <typename S>
  const_map_strategy<S> const_map(const S& s) {
    return const_map_strategy<S>(s);
  }

}

#endif