tuples.hh

// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
// $Id$
#ifndef DUNE_TUPLES_HH
#define DUNE_TUPLES_HH

#include <ostream>
#include "typetraits.hh"
#include "static_assert.hh"

#ifdef HAVE_TUPLE
#include <tuple>
#elif defined HAVE_TR1_TUPLE
#include <tr1/tuple>
#endif

namespace Dune {
  /** @addtogroup Common
   *
   * @{
   */
  /**
   * @file
   * @brief Contains classes that implement tuples.
   *
   * This a refined implementation of the approach defined in
   * in the article &quot;Tuples and multiple return values
   * in C++&quot; of Jaakko J&auml;rvi (Turku Centre of Computer
   * Science, TUCS Technical Report No 249, March 1999,
   * ISBN 952-12-0401-X, ISSN 1239-1891) available from the
   * <a href="http://www.tucs.fi/publications/">TUCS publications archive</a>
   * @author Markus Blatt
   */


  template<class T>
  struct TupleAccessTraits
  {
    typedef typename ConstantVolatileTraits<T>::ConstType& ConstType;
    typedef T& NonConstType;
    typedef const typename ConstantVolatileTraits<T>::UnqualifiedType& ParameterType;
  };

  template<class T>
  struct TupleAccessTraits<T*>
  {
    typedef typename ConstantVolatileTraits<T>::ConstType* ConstType;
    typedef T* NonConstType;
    typedef T* ParameterType;
  };

  template<class T>
  struct TupleAccessTraits<T&>
  {
    typedef typename ConstantVolatileTraits<T>::ConstType& ConstType;
    typedef T& NonConstType;
    typedef T& ParameterType;
  };

#ifdef HAVE_TUPLE
  using std::tuple;
#elif defined HAVE_TR1_TUPLE
  using std::tr1::tuple;
#else
  /**
   * @brief An empty class.
   */
  struct Nil
  {};

  namespace
  {
    inline const Nil nullType()
    {
      return Nil();
    }
  }

  /**
   * @brief A tuple consisting of two objects.
   *
   * This is similar to std::pair
   */
  template<typename T1, typename TT>
  struct Pair
  {
    /**
     * @brief The type of the first field.
     */
    typedef T1 Type1;

    /**
     * @brief The type of the second field.
     */
    typedef TT Type2;
    //     enum{
    //     /**
    //      * @brief The number of values we hold.
    //      */
    //       values = 2;
    //     };

    /**
     * @brief Constructor
     *
     * @param t1 The value of the first field.
     * @param t2 The value of the second field.
     */
    template<typename T2, typename T3, typename T4, typename T5,
        typename T6, typename T7, typename T8, typename T9>
    Pair(typename TupleAccessTraits<T1>::ParameterType t1, T2& t2, T3& t3, T4& t4, T5& t5,
         T6& t6, T7& t7, T8& t8, T9& t9);

    /**
     * @brief Constructor
     *
     * @param t1 The value of the first field.
     * @param t2 The value of the second field.
     */
    Pair(typename TupleAccessTraits<Type1>::ParameterType t1, TT& t2);

    Pair();

    /**
     * @brief Copy Constructor for implicit type conversion
     * @param other The tuple to copy.
     */
    template<typename U1, typename U2>
    Pair(const Pair<U1,U2>& other);

    /**
     * @brief Assignment operator for implicit type conversion
     * @param other The tuple to assign.
     */
    template<typename U1, typename U2>
    Pair& operator=(const Pair<U1,U2>& other);

    Pair& operator=(const Pair& other);

    /**
     * @brief Get the first value
     * @return The first value
     */
    typename TupleAccessTraits<Type1>::NonConstType first();

    /**
     * @brief Get the first value
     * @return The first value
     */
    typename TupleAccessTraits<Type1>::ConstType
    first() const;

    /**
     * @brief Get the second value
     * @return The second value
     */
    typename TupleAccessTraits<Type2>::NonConstType
    second();

    /**
     * @brief Get the second value
     * @return The second value
     */
    typename TupleAccessTraits<Type2>::ConstType
    second() const;

    /** @brief The value of the first field. */
    Type1 first_;
    /** @brief The value of the second field. */
    Type2 second_;

  };

  /**
   * @brief A tuple consisting of one object.
   * Specialization of Pair that really is a single value.
   */
  template<typename T1>
  struct Pair<T1,Nil>
  {
    /**
     * @brief The type of the first field.
     */
    typedef T1 Type1;

    /**
     * @brief The type of the (non-existent) second field is Nil.
     * This typedef is useful in template metaprogramming, since it allows
     * you to specialise for Nil instead of Pair<T, Nil>
     */
    typedef Nil Type2;

    /**
     * @brief Constructor.
     * @param t1 The values for the first field.
     * @param t2 The value for the second field.
     */
    Pair(typename TupleAccessTraits<T1>::ParameterType first, const Nil&, const Nil&, const Nil&, const Nil&,
         const Nil&, const Nil&, const Nil&, const Nil&);

    /**
     * @brief Constructor.
     * @param t1 The values for the first field.
     * @param t2 The value for the second field.
     */
    Pair(typename TupleAccessTraits<T1>::ParameterType first,
         const Nil&);

    Pair();

    /**
     * @brief Copy constructor for type conversion.
     */
    template<typename T2>
    Pair(const Pair<T2,Nil>& other);

    /**
     * @brief Assignment operator for type conversion.
     */
    template<typename T2>
    Pair& operator=(const Pair<T2,Nil>& other);

    /**
     * @brief Assignment operator.
     */
    Pair& operator=(const Pair& other);

    /**
     * @brief Get the first value
     * @return The first value
     */
    typename TupleAccessTraits<Type1>::NonConstType
    first();

    /**
     * @brief Get the first value
     * @return The first value
     */
    typename TupleAccessTraits<Type1>::ConstType
    first() const;

    /** @brief The value of the first field.*/
    Type1 first_;
  };


  /**
   * @brief Converts the Tuple to a list of pairs.
   */
  template<typename T1, typename T2, typename T3, typename T4, typename T5,
      typename T6, typename T7, typename T8, typename T9>
  struct TupleToPairs
  {
    typedef Pair<T1, typename TupleToPairs<T2,T3,T4,T5,T6,T7,T8,T9,Nil>::Type > Type;
  };

  /**
   * @brief Specialization for a tuple consisting only of one type.
   */
  template<typename T1>
  struct TupleToPairs<T1,Nil,Nil,Nil,Nil,Nil,Nil,Nil,Nil>
  {
    typedef Pair<T1,Nil> Type;
  };

  /**
   * @brief A Tuple of objects.
   *
   * A maximum of 9 objects is supported.
   *
   * Use the following construction to access the individual elements.
     \code
      tuple<std::string, float*, int> my_tuple;

      std:string& s = get<0>(my_tuple);
      float*      p = get<1>(my_tuple);

      // Access the third element in a generic way
      typedef tuple_element<2, tuple<std::string, float*, int> >::type Type;
      Type&       i = get<2>(my_tuple);
     \endcode
   */
  template<typename T1, typename T2 = Nil, typename T3 = Nil,
      typename T4 = Nil, typename T5 = Nil,typename T6 = Nil,
      typename T7 = Nil, typename T8 = Nil, typename T9 = Nil>
  class tuple : public TupleToPairs<T1,T2,T3,T4,T5,T6,T7,T8,T9>::Type
  {
  public:
    //! Type of the first Pair defining the Tuple
    typedef typename TupleToPairs<T1,T2,T3,T4,T5,T6,T7,T8,T9>::Type FirstPair;

    tuple()
    {}

    tuple(typename TupleAccessTraits<T1>::ParameterType t1)
      : FirstPair(t1, nullType(), nullType(), nullType(),
                  nullType(), nullType(), nullType(), nullType(),
                  nullType())
    {}

    tuple(typename TupleAccessTraits<T1>::ParameterType t1,
          typename TupleAccessTraits<T2>::ParameterType t2)
      : FirstPair(t1, t2, nullType(), nullType(),
                  nullType(), nullType(), nullType(), nullType(),
                  nullType())
    {}

    tuple(typename TupleAccessTraits<T1>::ParameterType t1,
          typename TupleAccessTraits<T2>::ParameterType t2,
          typename TupleAccessTraits<T3>::ParameterType t3)
      : FirstPair(t1, t2, t3, nullType(),
                  nullType(), nullType(), nullType(), nullType(),
                  nullType())
    {}

    tuple(typename TupleAccessTraits<T1>::ParameterType t1,
          typename TupleAccessTraits<T2>::ParameterType t2,
          typename TupleAccessTraits<T3>::ParameterType t3,
          typename TupleAccessTraits<T4>::ParameterType t4)
      : FirstPair(t1, t2, t3, t4,
                  nullType(), nullType(), nullType(), nullType(),
                  nullType())
    {}

    tuple(typename TupleAccessTraits<T1>::ParameterType t1,
          typename TupleAccessTraits<T2>::ParameterType t2,
          typename TupleAccessTraits<T3>::ParameterType t3,
          typename TupleAccessTraits<T4>::ParameterType t4,
          typename TupleAccessTraits<T5>::ParameterType t5)
      : FirstPair(t1, t2, t3, t4,
                  t5, nullType(), nullType(), nullType(),
                  nullType())
    {}

    tuple(typename TupleAccessTraits<T1>::ParameterType t1,
          typename TupleAccessTraits<T2>::ParameterType t2,
          typename TupleAccessTraits<T3>::ParameterType t3,
          typename TupleAccessTraits<T4>::ParameterType t4,
          typename TupleAccessTraits<T5>::ParameterType t5,
          typename TupleAccessTraits<T6>::ParameterType t6)
      : FirstPair(t1, t2, t3, t4,
                  t5, t6, nullType(), nullType(),
                  nullType())
    {}

    tuple(typename TupleAccessTraits<T1>::ParameterType t1,
          typename TupleAccessTraits<T2>::ParameterType t2,
          typename TupleAccessTraits<T3>::ParameterType t3,
          typename TupleAccessTraits<T4>::ParameterType t4,
          typename TupleAccessTraits<T5>::ParameterType t5,
          typename TupleAccessTraits<T6>::ParameterType t6,
          typename TupleAccessTraits<T7>::ParameterType t7)
      : FirstPair(t1, t2, t3, t4,
                  t5, t6, t7, nullType(),
                  nullType())
    {}

    tuple(typename TupleAccessTraits<T1>::ParameterType t1,
          typename TupleAccessTraits<T2>::ParameterType t2,
          typename TupleAccessTraits<T3>::ParameterType t3,
          typename TupleAccessTraits<T4>::ParameterType t4,
          typename TupleAccessTraits<T5>::ParameterType t5,
          typename TupleAccessTraits<T6>::ParameterType t6,
          typename TupleAccessTraits<T7>::ParameterType t7,
          typename TupleAccessTraits<T8>::ParameterType t8)
      : FirstPair(t1, t2, t3, t4,
                  t5, t6, t7, t8,
                  nullType())
    {}

    tuple(typename TupleAccessTraits<T1>::ParameterType t1,
          typename TupleAccessTraits<T2>::ParameterType t2,
          typename TupleAccessTraits<T3>::ParameterType t3,
          typename TupleAccessTraits<T4>::ParameterType t4,
          typename TupleAccessTraits<T5>::ParameterType t5,
          typename TupleAccessTraits<T6>::ParameterType t6,
          typename TupleAccessTraits<T7>::ParameterType t7,
          typename TupleAccessTraits<T8>::ParameterType t8,
          typename TupleAccessTraits<T9>::ParameterType t9)
      : FirstPair(t1, t2, t3, t4, t5, t6, t7, t8, t9)
    {}

    template<class U1, class U2>
    tuple& operator=(const Pair<U1,U2>& other)
    {
      FirstPair::operator=(other);
      return *this;
    }
  };

#endif

#ifdef HAVE_TUPLE
  using std::tuple_element;
#elif defined HAVE_TR1_TUPLE
  using std::tr1::tuple_element;
#else
  /**
   * @brief Get the type of the N-th element of the tuple.
   */
  template<int N, class Tuple>
  struct tuple_element
  {
    /**
     * @brief The type of the N-th element of the tuple.
     */
    typedef typename tuple_element<N,typename Tuple::FirstPair>::type type;
    typedef typename tuple_element<N,typename Tuple::FirstPair>::type Type;
  };

  template<int N, typename T1, typename T2>
  struct tuple_element<N,Pair<T1,T2> >
  {
    /**
     * @brief The type of the N-th element of the tuple.
     */
    typedef typename tuple_element<N-1,T2>::Type type;
    typedef typename tuple_element<N-1,T2>::Type Type;
  };

  /**
   * @brief Get the type of the first element of the tuple.
   */
  template<typename T1, typename T2>
  struct tuple_element<0, Pair<T1,T2> >
  {
    /**
     * @brief The type of the first element of the tuple.
     */
    typedef T1 type;
    typedef T1 Type;
  };

#endif

  template< int N, class T >
  struct ElementType
  {
    typedef typename tuple_element< N, T > :: type Type DUNE_DEPRECATED;
  };

#if defined HAVE_TUPLE || defined HAVE_TR1_TUPLE
#ifdef HAVE_TUPLE
  #define TUPLE_NS std
  using std::get;
#elif defined HAVE_TR1_TUPLE
  #define TUPLE_NS std::tr1
  using std::tr1::get;
#endif

  // for backwards compatibility
  template<int i>
  struct Element {
    template<typename T1>
    static typename TupleAccessTraits<typename tuple_element<i,T1>::type>::NonConstType get(T1& t)
    {
      return TUPLE_NS::get<i>(t);
    }

    template<typename T1>
    static typename TupleAccessTraits<typename tuple_element<i,T1>::type>::ConstType get(const T1& t)
    {
      return TUPLE_NS::get<i>(t);
    }
  };
  #undef TUPLE_NS

#else
  /**
   * @brief Get the N-th element of a tuple.
   */
  template<int N>
  struct Element
  {
    /**
     * @brief Get the N-th element of the tuple.
     * @param tuple The tuple whose N-th element we want.
     * @return The N-th element of the tuple.
     */
    template<typename T1, typename T2>
    static typename TupleAccessTraits<
        typename tuple_element<N,Pair<T1,T2> >::type
        >::NonConstType
    get(Pair<T1,T2>& tuple)
    {
      return Element<N-1>::get(tuple.second());
    }

    /**
     * @brief Get the N-th element of the tuple.
     * @param tuple The tuple whose N-th element we want.
     * @return The N-th element of the tuple.
     */
    template<typename T1, typename T2>
    static typename TupleAccessTraits<
        typename tuple_element<N,Pair<T1,T2> >::type
        >::ConstType
    get(const Pair<T1,T2>& tuple)
    {
      return Element<N-1>::get(tuple.second());
    }
  };

  /**
   * @brief Get the first element of a tuple.
   */
  template<>
  struct Element<0>
  {
    /**
     * @brief Get the first element of the tuple.
     * @param tuple The tuple whose first element we want.
     * @return The first element of the tuple.
     */
    template<typename T1, typename T2>
    static typename TupleAccessTraits<T1>::NonConstType get(Pair<T1,T2>& tuple)
    {
      return tuple.first();
    }

    /**
     * @brief Get the first element of the tuple.
     * @param tuple The tuple whose first element we want.
     * @return The first element of the tuple.
     */
    template<typename T1, typename T2>
    static typename TupleAccessTraits<T1>::ConstType get(const Pair<T1,T2>& tuple)
    {
      return tuple.first();
    }
  };

  template<int i, typename T1, typename T2, typename T3, typename T4,
      typename T5, typename T6, typename T7, typename T8, typename T9>
  typename TupleAccessTraits<typename tuple_element<i, tuple<T1,T2,T3,T4,T5,T6,T7,T8,T9> >::type>
  ::NonConstType
  get(tuple<T1,T2,T3,T4,T5,T6,T7,T8,T9>& t)
  {
    return Element<i>::get(t);
  }

  template<int i, typename T1, typename T2, typename T3, typename T4,
      typename T5, typename T6, typename T7, typename T8, typename T9>
  typename TupleAccessTraits<typename tuple_element<i, tuple<T1,T2,T3,T4,T5,T6,T7,T8,T9> >::type>
  ::ConstType
  get(const tuple<T1,T2,T3,T4,T5,T6,T7,T8,T9>& t)
  {
    return Element<i>::get(t);
  }

#endif

#ifdef HAVE_TUPLE
  using std::tuple_size;
#elif defined HAVE_TR1_TUPLE
  using std::tr1::tuple_size;
#else
  /**
   * @brief Template meta_programm to query the size of a tuple
   *
   */
  template<class T>
  struct tuple_size
  {
    enum {
      // @brief The number of Elements in the tuple.
      value=tuple_size<typename T::FirstPair>::value
    };


  };

  template<typename T1, typename T2>
  struct tuple_size<Pair<T1,T2> >
  {
    enum { value=1+tuple_size<T2>::value};
  };


  template<typename T1>
  struct tuple_size<Pair<T1,Nil> >
  {
    enum { value=1};
  };

  template<>
  struct tuple_size<Pair<Nil,Nil> >
  {
    enum { value=0};
  };
#endif
  template<typename T>
  struct Size : public tuple_size<T>
  {};


#ifdef HAVE_TUPLE
  using std::tie;
  using std::make_tuple;
#elif defined HAVE_TR1_TUPLE
  using std::tr1::tie;
  using std::tr1::make_tuple;
#endif


  template<int i>
  struct tuple_writer
  {
    template<class T>
    static std::ostream& put(std::ostream& os, const T& t, const char* delim=", ")
    {
      return tuple_writer<i-1>::put(os,t,delim)<<delim<<get<i-1>(t);
    }
  };

  template<>
  struct tuple_writer<1>
  {
    template<class T>
    static std::ostream& put(std::ostream& os, const T& t, const char* delim=", ")
    {
      return os<<get<0>(t);
    }
  };

  template<>
  struct tuple_writer<0>
  {
    template<class T>
    static std::ostream& put(std::ostream& os, const T& t, const char* delim=", ")
    {
      return os;
    }
  };

#if defined HAVE_TUPLE || defined HAVE_TR1_TUPLE
  /**
   * \brief Print a tuple.
   */
  template<typename T1>
  inline std::ostream& operator<<( std::ostream& os, const tuple<T1> & t)
  {
    typedef tuple<T1> TupleT;
    return tuple_writer<tuple_size<TupleT>::value>::put(os, t);
  }

  template<typename T1, typename T2>
  inline std::ostream& operator<<( std::ostream& os, const tuple<T1,T2> & t)
  {
    typedef tuple<T1,T2> TupleT;
    return tuple_writer<tuple_size<TupleT>::value>::put(os, t);
  }

  template<typename T1, typename T2, typename T3>
  inline std::ostream& operator<<( std::ostream& os, const tuple<T1,T2,T3> & t)
  {
    typedef tuple<T1,T2,T3> TupleT;
    return tuple_writer<tuple_size<TupleT>::value>::put(os, t);
  }

  template<typename T1, typename T2, typename T3, typename T4>
  inline std::ostream& operator<<( std::ostream& os, const tuple<T1,T2,T3,T4> & t)
  {
    typedef tuple<T1,T2,T3,T4> TupleT;
    return tuple_writer<tuple_size<TupleT>::value>::put(os, t);
  }

  template<typename T1, typename T2, typename T3, typename T4, typename T5>
  inline std::ostream& operator<<( std::ostream& os, const tuple<T1,T2,T3,T4,T5> & t)
  {
    typedef tuple<T1,T2,T3,T4,T5> TupleT;
    return tuple_writer<tuple_size<TupleT>::value>::put(os, t);
  }

  template<typename T1, typename T2, typename T3, typename T4, typename T5, typename T6>
  inline std::ostream& operator<<( std::ostream& os, const tuple<T1,T2,T3,T4,T5,T6> & t)
  {
    typedef tuple<T1,T2,T3,T4,T5,T6> TupleT;
    return tuple_writer<tuple_size<TupleT>::value>::put(os, t);
  }

  template<typename T1, typename T2, typename T3, typename T4, typename T5, typename T6, typename T7>
  inline std::ostream& operator<<( std::ostream& os, const tuple<T1,T2,T3,T4,T5,T6,T7> & t)
  {
    typedef tuple<T1,T2,T3,T4,T5,T6,T7> TupleT;
    return tuple_writer<tuple_size<TupleT>::value>::put(os, t);
  }

  template<typename T1, typename T2, typename T3, typename T4, typename T5, typename T6, typename T7,
      typename T8>
  inline std::ostream& operator<<( std::ostream& os, const tuple<T1,T2,T3,T4,T5,T6,T7,T8> & t)
  {
    typedef tuple<T1,T2,T3,T4,T5,T6,T7,T8> TupleT;
    return tuple_writer<tuple_size<TupleT>::value>::put(os, t);
  }

  template<typename T1, typename T2, typename T3, typename T4, typename T5, typename T6, typename T7,
      typename T8, typename T9>
  inline std::ostream& operator<<( std::ostream& os, const tuple<T1,T2,T3,T4,T5,T6,T7,T8,T9> & t)
  {
    typedef tuple<T1,T2,T3,T4,T5,T6,T7,T8,T9> TupleT;
    return tuple_writer<tuple_size<TupleT>::value>::put(os, t);
  }

  template<typename T1, typename T2, typename T3, typename T4, typename T5, typename T6, typename T7,
      typename T8, typename T9, typename T10>
  inline std::ostream& operator<<( std::ostream& os, const tuple<T1,T2,T3,T4,T5,T6,T7,T8,T9,T10> & t)
  {
    typedef tuple<T1,T2,T3,T4,T5,T6,T7,T8,T9,T10> TupleT;
    return tuple_writer<tuple_size<TupleT>::value>::put(os, t);
  }

#else
  /**
   * @brief Equality comparison operator for tuples.
   * @param tuple1 The first tuple.
   * @param tuple2 The second tuple,
   */
  template<typename T1, typename T2, typename U1, typename U2>
  inline bool operator==(const Pair<T1,T2>& tuple1, const Pair<U1,U2>& tuple2)
  {
    return (tuple1.first()==tuple2.first() && tuple1.second()==tuple2.second());
  }

  /**
   * @brief Inequality comparison operator for tuples.
   * @param tuple1 The first tuple.
   * @param tuple2 The second tuple,
   */
  template<typename T1, typename T2, typename U1, typename U2>
  inline bool operator!=(const Pair<T1,T2>& tuple1, const Pair<U1,U2>& tuple2)
  {
    return (tuple1.first()!=tuple2.first() || tuple1.second()!=tuple2.second());
  }

  /**
   * @brief Less operator for tuples.
   * @param tuple1 The first tuple.
   * @param tuple2 The second tuple,
   */
  template<typename T1, typename T2, typename U1, typename U2>
  inline bool operator<(const Pair<T1,T2>& tuple1, const Pair<U1,U2>& tuple2)
  {
    return tuple1.first() < tuple2.first()
           || (tuple1.first() == tuple2.first() && tuple1.second() < tuple2.second());
  }

  /**
   * @brief Equality comparison operator for tuples.
   * @param tuple1 The first tuple.
   * @param tuple2 The second tuple,
   */
  template<typename T1,typename U1>
  inline bool operator==(const Pair<T1,Nil>& tuple1, const Pair<U1,Nil>& tuple2)
  {
    return (tuple1.first()==tuple2.first());
  }

  /**
   * @brief Inequality comparison operator for tuples.
   * @param tuple1 The first tuple.
   * @param tuple2 The second tuple,
   */
  template<typename T1, typename U1>
  inline bool operator!=(const Pair<T1,Nil>& tuple1, const Pair<U1,Nil>& tuple2)
  {
    dune_static_assert( (IsInteroperable<T1,U1>::value),
                        "T1 and U1 have to be interoperable, i.e., either "
                        "conversion from one to the other must exist." );
    return (tuple1.first()!=tuple2.first());
  }

  /**
   * @brief Less operator for tuples.
   * @param tuple1 The first tuple.
   * @param tuple2 The second tuple,
   */
  template<typename T1, typename U1>
  inline bool operator<(const Pair<T1,Nil>& tuple1, const Pair<U1,Nil>& tuple2)
  {
    return (tuple1.first()<tuple2.first());
  }

  /**
   * @brief Equality comparison operator for tuples.
   *
   * @param tuple1 The first tuple.
   * @param tuple2 The second tuple.
   * @return False as the type of the compared objects are different.
   */
  template<typename T1,typename U1, typename U2>
  inline bool operator==(const Pair<T1,Nil>& tuple1, const Pair<U1,U2>& tuple2)
  {
    return false;
  }

  /**
   * @brief Inequality comparison operator for tuples.
   * @param tuple1 The first tuple.
   * @param tuple2 The second tuple.
   * @return True as the type of the compared objects are different.
   */
  template<typename T1, typename U1, typename U2>
  inline bool operator!=(const Pair<T1,Nil>& tuple1, const Pair<U1,U2>& tuple2)
  {
    return true;
  }


  /**
   * @brief Equality comparison operator for tuples.
   * @param tuple1 The first tuple.
   * @param tuple2 The second tuple.
   * @return False as the type of the compared objects are different.
   */
  template<typename T1, typename T2, typename U1>
  inline bool operator==(const Pair<T1,T2>& tuple1, const Pair<U1,Nil>& tuple2)
  {
    return false;
  }

  /**
   * @brief Inequality comparison operator for tuples.
   * @param tuple1 The first tuple.
   * @param tuple2 The second tuple.
   * @return True as the type of the compared objects are different.
   */
  template<typename T1, typename T2, typename U1>
  inline bool operator!=(const Pair<T1,T2>& tuple1, const Pair<U1,Nil>& tuple2)
  {
    return true;
  }

  /**
   * @brief Create a tuple and initialize it.
   * @param first The value of the first field.
   * @param second The value of the second field.
   */
  template<typename T1, typename T2>
  inline Pair<T1,T2> makePair(const T1& first, const T2& second)
  {
    return Pair<T1,T2>(first, second);
  }

  /**
   * @brief Print aa pair or  tuple.
   */
  template<typename T1, typename T2>
  inline std::ostream& operator<<(std::ostream& os, const Pair<T1,T2>& pair)
  {
    os<<pair.first()<<" "<<pair.second();
    return os;
  }

  template<typename T1>
  inline std::ostream& operator<<(std::ostream& os, const Pair<T1,Nil>& pair)
  {
    os<<pair.first();
    return os;
  }

  template<class T1>
  inline tuple<T1&> tie(T1& t1) {
    return tuple<T1&> (t1);
  }

  template<class T1, class T2>
  inline tuple<T1&, T2&> tie(T1& t1, T2& t2) {
    return tuple<T1&, T2&> (t1, t2);
  }

  template<class T1, class T2, class T3>
  inline tuple<T1&, T2&, T3&> tie(T1& t1, T2& t2, T3& t3) {
    return tuple<T1&, T2&, T3&> (t1, t2, t3);
  }

  template<class T1, class T2, class T3, class T4>
  inline tuple<T1&, T2&, T3&, T4&> tie(T1& t1, T2& t2, T3& t3, T4& t4) {
    return tuple<T1&, T2&, T3&, T4&> (t1, t2, t3, t4);
  }

  template<class T1, class T2, class T3, class T4, class T5>
  inline tuple<T1&, T2&, T3&, T4&, T5&>
  tie(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5) {
    return tuple<T1&, T2&, T3&, T4&, T5&> (t1, t2, t3, t4, t5);
  }

  template<class T1, class T2, class T3, class T4, class T5, class T6>
  inline tuple<T1&, T2&, T3&, T4&, T5&, T6&>
  tie(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5, T6& t6) {
    return tuple<T1&, T2&, T3&, T4&, T5&, T6&> (t1, t2, t3, t4, t5, t6);
  }

  template<class T1, class T2, class T3, class T4, class T5, class T6, class T7>
  inline tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&>
  tie(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5, T6& t6, T7& t7) {
    return tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&> (t1, t2, t3, t4, t5, t6, t7);
  }

  template<class T1, class T2, class T3, class T4, class T5, class T6, class T7,
      class T8>
  inline tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&, T8&>
  tie(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5, T6& t6, T7& t7, T8& t8) {
    return tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&, T8&>
             (t1, t2, t3, t4, t5, t6, t7, t8);
  }

  template<class T1, class T2, class T3, class T4, class T5, class T6, class T7,
      class T8, class T9>
  inline tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&, T8&, T9&>
  tie(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5, T6& t6, T7& t7, T8& t8, T9& t9) {
    return tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&, T8&, T9&>
             (t1, t2, t3, t4, t5, t6, t7, t8, t9);
  }

  template<class T1>
  inline tuple<T1> make_tuple(const T1& t1) {
    return tuple<T1> (t1);
  }

  template<class T1, class T2>
  inline tuple<T1, T2> make_tuple(const T1& t1, const T2& t2) {
    return tuple<T1, T2> (t1, t2);
  }

  template<class T1, class T2, class T3>
  inline tuple<T1, T2, T3> make_tuple(const T1& t1, const T2& t2, const T3& t3) {
    return tuple<T1, T2, T3> (t1, t2, t3);
  }

  template<class T1, class T2, class T3, class T4>
  inline tuple<T1, T2, T3, T4> make_tuple(const T1& t1, const T2& t2, const T3& t3, const T4& t4) {
    return tuple<T1, T2, T3, T4> (t1, t2, t3, t4);
  }

  template<class T1, class T2, class T3, class T4, class T5>
  inline tuple<T1, T2, T3, T4, T5>
  make_tuple(const T1& t1, const T2& t2, const T3& t3, const T4& t4, const T5& t5) {
    return tuple<T1, T2, T3, T4, T5> (t1, t2, t3, t4, t5);
  }

  template<class T1, class T2, class T3, class T4, class T5, class T6>
  inline tuple<T1, T2, T3, T4, T5, T6>
  make_tuple(const T1& t1, const T2& t2, const T3& t3, const T4& t4, const T5& t5, const T6& t6) {
    return tuple<T1, T2, T3, T4, T5, T6> (t1, t2, t3, t4, t5, t6);
  }

  template<class T1, class T2, class T3, class T4, class T5, class T6, class T7>
  inline tuple<T1, T2, T3, T4, T5, T6, T7>
  make_tuple(const T1& t1, const T2& t2, const T3& t3, const T4& t4, const T5& t5, const T6& t6,
             const T7& t7) {
    return tuple<T1, T2, T3, T4, T5, T6, T7> (t1, t2, t3, t4, t5, t6, t7);
  }

  template<class T1, class T2, class T3, class T4, class T5, class T6, class T7,
      class T8>
  inline tuple<T1, T2, T3, T4, T5, T6, T7, T8>
  make_tuple(const T1& t1, const T2& t2, const T3& t3, const T4& t4, const T5& t5, const T6& t6,
             const T7& t7, const T8& t8) {
    return tuple<T1, T2, T3, T4, T5, T6, T7, T8>
             (t1, t2, t3, t4, t5, t6, t7, t8);
  }

  template<class T1, class T2, class T3, class T4, class T5, class T6, class T7,
      class T8, class T9>
  inline tuple<T1, T2, T3, T4, T5, T6, T7, T8, T9>
  make_tuple(const T1& t1, const T2& t2, const T3& t3, const T4& t4, const T5& t5, const T6& t6,
             const T7& t7, const T8& t8, const T9& t9) {
    return tuple<T1, T2, T3, T4, T5, T6, T7, T8, T9>
             (t1, t2, t3, t4, t5, t6, t7, t8, t9);
  }

  template<typename T1, typename TT>
  template<typename T2, typename T3, typename T4, typename T5,
      typename T6, typename T7, typename T8, typename T9>
  inline Pair<T1,TT>::Pair(typename TupleAccessTraits<T1>::ParameterType first,
                           T2& t2, T3& t3, T4& t4, T5& t5,
                           T6& t6, T7& t7, T8& t8, T9& t9)
    : first_(first), second_(t2,t3,t4,t5,t6,t7,t8,t9, nullType())
  {}

  template <typename T1, typename TT>
  inline Pair<T1, TT>::Pair(typename TupleAccessTraits<T1>::ParameterType first, TT& second)
    : first_(first), second_(second)
  {}

  template<typename T1, typename T2>
  inline Pair<T1,T2>::Pair()
    : first_(), second_()
  {}

  template<typename T1, typename T2>
  template<typename U1, typename U2>
  inline Pair<T1,T2>::Pair(const Pair<U1,U2>& other)
    : first_(other.first_), second_(other.second_)
  {}

  template<typename T1, typename T2>
  template<typename U1, typename U2>
  inline Pair<T1,T2>& Pair<T1,T2>::operator=(const Pair<U1,U2>& other)