ceph/src/boost/libs/proto/include/boost/proto/functional/range/begin.hpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 /// \file begin.hpp
   3 /// Proto callables for boost::begin()
   4 //
   5 //  Copyright 2012 Eric Niebler. Distributed under the Boost
   6 //  Software License, Version 1.0. (See accompanying file
   7 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   8
   9 #ifndef BOOST_PROTO_FUNCTIONAL_RANGE_BEGIN_HPP_EAN_27_08_2012
  10 #define BOOST_PROTO_FUNCTIONAL_RANGE_BEGIN_HPP_EAN_27_08_2012
  11
  12 #include <boost/range/begin.hpp>
  13 #include <boost/proto/proto_fwd.hpp>
  14
  15 namespace boost { namespace proto { namespace functional
  16 {
  17
  18     // A PolymorphicFunctionObject that wraps boost::begin()
  19     struct begin
  20     {
  21         BOOST_PROTO_CALLABLE()
  22
  23         template<typename Sig>
  24         struct result;
  25
  26         template<typename This, typename Rng>
  27         struct result<This(Rng)>
  28           : boost::range_iterator<Rng const>
  29         {};
  30
  31         template<typename This, typename Rng>
  32         struct result<This(Rng &)>
  33           : boost::range_iterator<Rng>
  34         {};
  35
  36         template<typename Rng>
  37         typename boost::range_iterator<Rng>::type operator()(Rng &rng) const
  38         {
  39             return boost::begin(rng);
  40         }
  41
  42         template<typename Rng>
  43         typename boost::range_iterator<Rng const>::type operator()(Rng const &rng) const
  44         {
  45             return boost::begin(rng);
  46         }
  47     };
  48
  49 }}}
  50
  51 #endif