couple_letter.hh

// couple_letter.hh: this file is part of the Vaucanson project.
//
// Vaucanson, a generic library for finite state machines.
//
// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006 The Vaucanson Group.
//
// 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 2
// of the License, or (at your option) any later version.
//
// The complete GNU General Public Licence Notice can be found as the
// `COPYING' file in the root directory.
//
// The Vaucanson Group consists of people listed in the `AUTHORS' file.
//
#ifndef VCSN_ALGEBRA_IMPLEMENTATION_LETTER_COUPLE_LETTER_HH
# define VCSN_ALGEBRA_IMPLEMENTATION_LETTER_COUPLE_LETTER_HH

# include <climits>
# include <string>
# include <iostream>

# include <vaucanson/algebra/concept/letter.hh>
# include <vaucanson/algebra/concept/freemonoid_base.hh>

// Here are functions to manipulate pairs.

namespace vcsn
{

  namespace algebra
  {

    template <typename U, typename V>
    struct letter_traits< std::pair<U, V> >
    {
        enum
        {
          /*
           * Theoretically   cardinal   should   be   the   product   of
           * letter_traits<U>::cardinal and letter_traits<V>::cardinal.
           * But to  avoid overflows and for
           * practical reasons, it is better to consider it infinite.
           *
           * FIXME: Maybe doing this is not a good idea?
           */
          cardinal = INT_MAX
        };

        static char default_epsilon()
        {
          return '1';
        }
    };

  } // End of namespace algebra.
} // End of namespace vcsn.

namespace vcsn {

  namespace algebra {

    // Specialization for pairs.
    template <typename S, typename U, typename V, typename CharContainer>
    bool op_parse (const algebra::FreeMonoidBase<S>& set,
                   std::basic_string< std::pair<U, V> >& v,
                   const std::string& s,
                   typename std::string::const_iterator& i,
                   const CharContainer& escaped);
  }
} //vcsn

namespace std {

  template <typename U, typename V>
  std::ostream& operator<< (std::ostream& o, std::pair<U, V> p);

  template <typename U, typename V, class Traits, class Allocator>
  std::ostream&
  operator<< (std::ostream& o,
              std::basic_string<std::pair<U, V>, Traits, Allocator> s);

  template <typename U, typename V>
  std::istream& operator>> (std::istream& i, std::pair<U, V>& p);

} // vcsn

# if !defined VCSN_USE_INTERFACE_ONLY || defined VCSN_USE_LIB
#  include <vaucanson/algebra/implementation/letter/couple_letter.hxx>
# endif // VCSN_USE_INTERFACE_ONLY

#endif // ! VCSN_ALGEBRA_IMPLEMENTATION_LETTER_COUPLE_LETTER_HH

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