137 lines
4.0 KiB
Plaintext
137 lines
4.0 KiB
Plaintext
/*=============================================================================
|
|
Copyright (c) 2001-2011 Joel de Guzman
|
|
|
|
Distributed under the Boost Software License, Version 1.0. (See accompanying
|
|
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
|
|
==============================================================================*/
|
|
#if !defined(FUSION_AT_IMPL_07172005_0726)
|
|
#define FUSION_AT_IMPL_07172005_0726
|
|
|
|
#include <boost/fusion/support/config.hpp>
|
|
#include <boost/fusion/support/detail/access.hpp>
|
|
#include <boost/type_traits/is_const.hpp>
|
|
#include <boost/type_traits/add_const.hpp>
|
|
#include <boost/mpl/if.hpp>
|
|
#include <boost/mpl/bool.hpp>
|
|
|
|
namespace boost { namespace fusion
|
|
{
|
|
namespace detail
|
|
{
|
|
template <typename Cons>
|
|
struct cons_deref
|
|
{
|
|
typedef typename Cons::car_type type;
|
|
};
|
|
|
|
template <typename Cons, int I>
|
|
struct cons_advance
|
|
{
|
|
typedef typename
|
|
cons_advance<Cons, I-1>::type::cdr_type
|
|
type;
|
|
};
|
|
|
|
template <typename Cons>
|
|
struct cons_advance<Cons, 0>
|
|
{
|
|
typedef Cons type;
|
|
};
|
|
|
|
template <typename Cons>
|
|
struct cons_advance<Cons, 1>
|
|
{
|
|
typedef typename Cons::cdr_type type;
|
|
};
|
|
|
|
template <typename Cons>
|
|
struct cons_advance<Cons, 2>
|
|
{
|
|
#if BOOST_WORKAROUND(BOOST_MSVC, > 1400) // VC8 and above
|
|
typedef typename Cons::cdr_type::cdr_type type;
|
|
#else
|
|
typedef typename Cons::cdr_type _a;
|
|
typedef typename _a::cdr_type type;
|
|
#endif
|
|
};
|
|
|
|
template <typename Cons>
|
|
struct cons_advance<Cons, 3>
|
|
{
|
|
#if BOOST_WORKAROUND(BOOST_MSVC, > 1400) // VC8 and above
|
|
typedef typename Cons::cdr_type::cdr_type::cdr_type type;
|
|
#else
|
|
typedef typename Cons::cdr_type _a;
|
|
typedef typename _a::cdr_type _b;
|
|
typedef typename _b::cdr_type type;
|
|
#endif
|
|
};
|
|
|
|
template <typename Cons>
|
|
struct cons_advance<Cons, 4>
|
|
{
|
|
#if BOOST_WORKAROUND(BOOST_MSVC, > 1400) // VC8 and above
|
|
typedef typename Cons::cdr_type::cdr_type::cdr_type::cdr_type type;
|
|
#else
|
|
typedef typename Cons::cdr_type _a;
|
|
typedef typename _a::cdr_type _b;
|
|
typedef typename _b::cdr_type _c;
|
|
typedef typename _c::cdr_type type;
|
|
#endif
|
|
};
|
|
}
|
|
|
|
struct cons_tag;
|
|
|
|
namespace extension
|
|
{
|
|
template <typename Tag>
|
|
struct at_impl;
|
|
|
|
template <>
|
|
struct at_impl<cons_tag>
|
|
{
|
|
template <typename Sequence, typename N>
|
|
struct apply
|
|
{
|
|
typedef typename detail::cons_deref<
|
|
typename detail::cons_advance<Sequence, N::value>::type>::type
|
|
element;
|
|
|
|
typedef typename
|
|
mpl::if_<
|
|
is_const<Sequence>
|
|
, typename detail::cref_result<element>::type
|
|
, typename detail::ref_result<element>::type
|
|
>::type
|
|
type;
|
|
|
|
template <typename Cons, int N2>
|
|
BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
|
|
static type
|
|
call(Cons& s, mpl::int_<N2>)
|
|
{
|
|
return call(s.cdr, mpl::int_<N2-1>());
|
|
}
|
|
|
|
template <typename Cons>
|
|
BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
|
|
static type
|
|
call(Cons& s, mpl::int_<0>)
|
|
{
|
|
return s.car;
|
|
}
|
|
|
|
BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
|
|
static type
|
|
call(Sequence& s)
|
|
{
|
|
return call(s, mpl::int_<N::value>());
|
|
}
|
|
};
|
|
};
|
|
}
|
|
}}
|
|
|
|
#endif
|