epoc32/include/stdapis/boost/variant/detail/enable_recursive_fwd.hpp
author William Roberts <williamr@symbian.org>
Wed, 31 Mar 2010 12:27:01 +0100
branchSymbian2
changeset 3 e1b950c65cb4
permissions -rw-r--r--
Attempt to represent the S^2->S^3 header reorganisation as a series of "hg rename" operations
williamr@2
     1
//-----------------------------------------------------------------------------
williamr@2
     2
// boost variant/detail/enable_recursive_fwd.hpp header file
williamr@2
     3
// See http://www.boost.org for updates, documentation, and revision history.
williamr@2
     4
//-----------------------------------------------------------------------------
williamr@2
     5
//
williamr@2
     6
// Copyright (c) 2003
williamr@2
     7
// Eric Friedman
williamr@2
     8
//
williamr@2
     9
// Distributed under the Boost Software License, Version 1.0. (See
williamr@2
    10
// accompanying file LICENSE_1_0.txt or copy at
williamr@2
    11
// http://www.boost.org/LICENSE_1_0.txt)
williamr@2
    12
williamr@2
    13
#ifndef BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_FWD_HPP
williamr@2
    14
#define BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_FWD_HPP
williamr@2
    15
williamr@2
    16
#include "boost/mpl/aux_/config/ctps.hpp"
williamr@2
    17
williamr@2
    18
#include "boost/mpl/bool_fwd.hpp"
williamr@2
    19
williamr@2
    20
#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
williamr@2
    21
#   include "boost/mpl/bool.hpp"
williamr@2
    22
#else
williamr@2
    23
#   include "boost/type_traits/is_base_and_derived.hpp"
williamr@2
    24
#endif
williamr@2
    25
williamr@2
    26
namespace boost {
williamr@2
    27
namespace detail { namespace variant {
williamr@2
    28
williamr@2
    29
///////////////////////////////////////////////////////////////////////////////
williamr@2
    30
// (detail) tag recursive_flag
williamr@2
    31
//
williamr@2
    32
// Signifies that the variant should perform recursive substituion.
williamr@2
    33
//
williamr@2
    34
williamr@2
    35
#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
williamr@2
    36
williamr@2
    37
template <typename T>
williamr@2
    38
struct recursive_flag
williamr@2
    39
{
williamr@2
    40
    typedef T type;
williamr@2
    41
};
williamr@2
    42
williamr@2
    43
#else // defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
williamr@2
    44
williamr@2
    45
struct recursive_flag_tag
williamr@2
    46
{
williamr@2
    47
};
williamr@2
    48
williamr@2
    49
template <typename T>
williamr@2
    50
struct recursive_flag
williamr@2
    51
    : recursive_flag_tag
williamr@2
    52
{
williamr@2
    53
    typedef T type;
williamr@2
    54
};
williamr@2
    55
williamr@2
    56
#endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION workaround
williamr@2
    57
williamr@2
    58
///////////////////////////////////////////////////////////////////////////////
williamr@2
    59
// (detail) metafunction is_recursive_flag
williamr@2
    60
//
williamr@2
    61
// Signifies that the variant should perform recursive substituion.
williamr@2
    62
//
williamr@2
    63
williamr@2
    64
#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
williamr@2
    65
williamr@2
    66
template <typename T>
williamr@2
    67
struct is_recursive_flag
williamr@2
    68
    : mpl::false_
williamr@2
    69
{
williamr@2
    70
};
williamr@2
    71
williamr@2
    72
template <typename T>
williamr@2
    73
struct is_recursive_flag< recursive_flag<T> >
williamr@2
    74
    : mpl::true_
williamr@2
    75
{
williamr@2
    76
};
williamr@2
    77
williamr@2
    78
#else // defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
williamr@2
    79
williamr@2
    80
template <typename T>
williamr@2
    81
struct is_recursive_flag
williamr@2
    82
    : is_base_and_derived< recursive_flag_tag,T >
williamr@2
    83
{
williamr@2
    84
};
williamr@2
    85
williamr@2
    86
#endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION workaround
williamr@2
    87
williamr@2
    88
///////////////////////////////////////////////////////////////////////////////
williamr@2
    89
// (detail) metafunction enable_recursive
williamr@2
    90
//
williamr@2
    91
// Attempts recursive_variant_ tag substitution, wrapping with
williamr@2
    92
// boost::recursive_wrapper if substituion occurs w/ non-indirect result
williamr@2
    93
// (i.e., not a reference or pointer) *and* NoWrapper is false_.
williamr@2
    94
//
williamr@2
    95
template <
williamr@2
    96
      typename T
williamr@2
    97
    , typename RecursiveVariant
williamr@2
    98
    , typename NoWrapper = mpl::false_
williamr@2
    99
    >
williamr@2
   100
struct enable_recursive;
williamr@2
   101
williamr@2
   102
///////////////////////////////////////////////////////////////////////////////
williamr@2
   103
// (detail) metafunction class quoted_enable_recursive
williamr@2
   104
//
williamr@2
   105
// Same behavior as enable_recursive metafunction (see above).
williamr@2
   106
//
williamr@2
   107
template <
williamr@2
   108
      typename RecursiveVariant
williamr@2
   109
    , typename NoWrapper = mpl::false_
williamr@2
   110
    >
williamr@2
   111
struct quoted_enable_recursive;
williamr@2
   112
williamr@2
   113
}} // namespace detail::variant
williamr@2
   114
} // namespace boost
williamr@2
   115
williamr@2
   116
#endif // BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_FWD_HPP