pair.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 __PAIR_HH
# define __PAIR_HH

# include <algorithm>
# include "../lists/listable.hh"

namespace aurelia {

  template <typename A, typename B>
  struct pair_pattern {
    typedef typename
    pattern_concept<typename pattern_model<A>::model>::check require1;
    typedef typename
    pattern_concept<typename pattern_model<B>::model>::check require2;

  private:
    A a;
    B b;
  public:
    typedef std::pair<typename pattern_model<A>::model::build_type,
                      typename pattern_model<B>::model::build_type> build_type;
    pair_pattern(const A& a, const B& b): a(a), b(b) {}

    build_type operator*() const {
      return build_type(*a, *b);
    }
    build_type operator=(const build_type& i) const {
      A ta(a);
      B tb(b);
      ta = i.first;
      tb = i.second;
      return i;
    }
  };


  template <typename A, typename B>
  struct pattern_model<pair_pattern<A, B> > {
    struct model {
      typedef typename
      pattern_concept<typename pattern_model<A>::model>::check require1;
      typedef typename
      pattern_concept<typename pattern_model<B>::model>::check require2;

      typedef pair_pattern<A, B> type;
      typedef typename pair_pattern<A, B>::build_type build_type;
    };
  };

  template <typename A, typename B>
  pair_pattern<A,B> p(const A& a, const B& b) {
    return pair_pattern<A,B>(a, b);
  }

  template <typename A, typename B>
  struct listable_model<pair_pattern<A, B> > {
    struct model {
      typedef pair_pattern<A,B> Type;
    };
  };

}

#endif