// Copyright (C) 2010 Laboratoire de Recherche et Développement de
// l'Epita (LRDE).
// Copyright (C) 2004  Laboratoire d'Informatique de Paris 6 (LIP6),
// département Systèmes Répartis Coopératifs (SRC), Université Pierre
// et Marie Curie.
//
// This file is part of Spot, a model checking library.
//
// Spot 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 2 of the License, or
// (at your option) any later version.
//
// Spot 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 Spot; see the file COPYING.  If not, write to the Free
// Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
// 02111-1307, USA.

#ifndef SPOT_LTLVISIT_SIMPFG_HH
# define SPOT_LTLVISIT_SIMPFG_HH

#include "clone.hh"

namespace spot
{
  namespace ltl
  {
    /// \brief Replace <code>true U f</code> and <code>false R g</code> by
    /// <code>F f</code> and <code>G g</code>.
    ///
    /// Perform the following rewriting (from left to right):
    ///
    /// - true U a = F a
    /// - a M true = F a
    /// - false R a = G a
    /// - a W false = G a
    ///
    /// \ingroup ltl_visitor
    class simplify_f_g_visitor : public clone_visitor
    {
      typedef clone_visitor super;
    public:
      simplify_f_g_visitor();
      virtual ~simplify_f_g_visitor();

      using super::visit;
      void visit(binop* bo);

      virtual formula* recurse(formula* f);
    };

    /// \brief Replace <code>true U f</code> and <code>false R g</code> by
    /// <code>F f</code> and <code>G g</code>.
    ///
    /// Perform the following rewriting (from left to right):
    ///
    /// - true U a = F a
    /// - a M true = F a
    /// - false R a = G a
    /// - a W false = G a
    ///
    /// \ingroup ltl_rewriting
    formula* simplify_f_g(const formula* f);
  }
}

#endif // SPOT_LTLVISIT_LUNABBREV_HH