boost/fusion/container/list/cons.hpp

   1 /*=============================================================================
   2     Copyright (c) 2001-2011 Joel de Guzman
   3     Copyright (c) 2005 Eric Niebler
   4
   5     Distributed under the Boost Software License, Version 1.0. (See accompanying
   6     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   7 ==============================================================================*/
   8 #if !defined(FUSION_CONS_07172005_0843)
   9 #define FUSION_CONS_07172005_0843
  10
  11 #include <boost/fusion/container/list/cons_fwd.hpp>
  12 #include <boost/fusion/support/detail/access.hpp>
  13 #include <boost/fusion/sequence/intrinsic/begin.hpp>
  14 #include <boost/fusion/sequence/intrinsic/end.hpp>
  15 #include <boost/fusion/iterator/next.hpp>
  16 #include <boost/fusion/iterator/deref.hpp>
  17 #include <boost/fusion/container/list/cons_iterator.hpp>
  18 #include <boost/fusion/container/list/detail/begin_impl.hpp>
  19 #include <boost/fusion/container/list/detail/end_impl.hpp>
  20 #include <boost/fusion/container/list/detail/at_impl.hpp>
  21 #include <boost/fusion/container/list/detail/value_at_impl.hpp>
  22 #include <boost/fusion/container/list/detail/empty_impl.hpp>
  23 #include <boost/type_traits/is_convertible.hpp>
  24 #include <boost/utility/enable_if.hpp>
  25 #include <boost/fusion/support/sequence_base.hpp>
  26 #include <boost/mpl/int.hpp>
  27 #include <boost/mpl/bool.hpp>
  28 #include <boost/mpl/or.hpp>
  29
  30 namespace boost { namespace fusion
  31 {
  32     struct void_;
  33     struct cons_tag;
  34     struct forward_traversal_tag;
  35     struct fusion_sequence_tag;
  36
  37     struct nil_ : sequence_base<nil_>
  38     {
  39         typedef mpl::int_<0> size;
  40         typedef cons_tag fusion_tag;
  41         typedef fusion_sequence_tag tag; // this gets picked up by MPL
  42         typedef mpl::false_ is_view;
  43         typedef forward_traversal_tag category;
  44         typedef void_ car_type;
  45         typedef void_ cdr_type;
  46
  47         nil_() {}
  48
  49         template <typename Iterator>
  50         nil_(Iterator const& /*iter*/, mpl::true_ /*this_is_an_iterator*/)
  51         {}
  52
  53         template <typename Iterator>
  54         void assign_from_iter(Iterator const& /*iter*/)
  55         {
  56         }
  57     };
  58
  59     template <typename Car, typename Cdr /*= nil_*/>
  60     struct cons : sequence_base<cons<Car, Cdr> >
  61     {
  62         typedef mpl::int_<Cdr::size::value+1> size;
  63         typedef cons_tag fusion_tag;
  64         typedef fusion_sequence_tag tag; // this gets picked up by MPL
  65         typedef mpl::false_ is_view;
  66         typedef forward_traversal_tag category;
  67         typedef Car car_type;
  68         typedef Cdr cdr_type;
  69
  70         cons()
  71             : car(), cdr() {}
  72
  73         explicit cons(typename detail::call_param<Car>::type in_car)
  74             : car(in_car), cdr() {}
  75
  76         cons(
  77             typename detail::call_param<Car>::type in_car
  78           , typename detail::call_param<Cdr>::type in_cdr)
  79             : car(in_car), cdr(in_cdr) {}
  80
  81         template <typename Car2, typename Cdr2>
  82         cons(cons<Car2, Cdr2> const& rhs)
  83             : car(rhs.car), cdr(rhs.cdr) {}
  84
  85         cons(cons const& rhs)
  86             : car(rhs.car), cdr(rhs.cdr) {}
  87
  88         template <typename Sequence>
  89         cons(
  90             Sequence const& seq
  91           , typename boost::disable_if<
  92                 mpl::or_<
  93                     is_convertible<Sequence, cons> // use copy ctor instead
  94                   , is_convertible<Sequence, Car>  // use copy to car instead
  95                 >
  96             >::type* /*dummy*/ = 0
  97         )
  98             : car(*fusion::begin(seq))
  99             , cdr(fusion::next(fusion::begin(seq)), mpl::true_()) {}
 100
 101         template <typename Iterator>
 102         cons(Iterator const& iter, mpl::true_ /*this_is_an_iterator*/)
 103             : car(*iter)
 104             , cdr(fusion::next(iter), mpl::true_()) {}
 105
 106         template <typename Car2, typename Cdr2>
 107         cons& operator=(cons<Car2, Cdr2> const& rhs)
 108         {
 109             car = rhs.car;
 110             cdr = rhs.cdr;
 111             return *this;
 112         }
 113
 114         cons& operator=(cons const& rhs)
 115         {
 116             car = rhs.car;
 117             cdr = rhs.cdr;
 118             return *this;
 119         }
 120
 121         template <typename Sequence>
 122         typename boost::disable_if<is_convertible<Sequence, Car>, cons&>::type
 123         operator=(Sequence const& seq)
 124         {
 125             typedef typename result_of::begin<Sequence const>::type Iterator;
 126             Iterator iter = fusion::begin(seq);
 127             this->assign_from_iter(iter);
 128             return *this;
 129         }
 130
 131         template <typename Iterator>
 132         void assign_from_iter(Iterator const& iter)
 133         {
 134             car = *iter;
 135             cdr.assign_from_iter(fusion::next(iter));
 136         }
 137
 138         car_type car;
 139         cdr_type cdr;
 140     };
 141 }}
 142
 143 #endif
 144