1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
|
// Copyright Daniel Wallin, David Abrahams 2005.
// Copyright Cromwell D. Enage 2017.
// 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)
#ifndef DEFAULT_050329_HPP
#define DEFAULT_050329_HPP
namespace boost { namespace parameter { namespace aux {
// A wrapper for the default value passed by the user when resolving
// the value of the parameter with the given Keyword
template <typename Keyword, typename Value>
struct default_
{
inline BOOST_CONSTEXPR default_(Value& x) : value(x)
{
}
Value& value;
};
}}} // namespace boost::parameter::aux
#include <boost/parameter/config.hpp>
namespace boost { namespace parameter { namespace aux {
// lazy_default -- A wrapper for the default value computation function
// passed by the user when resolving the value of the parameter with the
// given keyword.
#if BOOST_WORKAROUND(__EDG_VERSION__, <= 300)
// These compilers need a little extra help with overload resolution;
// we have empty_arg_list's operator[] accept a base class
// to make that overload less preferable.
template <typename KW, typename DefaultComputer>
struct lazy_default_base
{
inline BOOST_CONSTEXPR lazy_default_base(DefaultComputer& x)
: compute_default(x)
{
}
DefaultComputer& compute_default;
};
template <typename KW, typename DefaultComputer>
struct lazy_default
: ::boost::parameter::aux::lazy_default_base<KW,DefaultComputer>
{
inline BOOST_CONSTEXPR lazy_default(DefaultComputer& x)
: ::boost::parameter::aux::lazy_default_base<KW,DefaultComputer>(x)
{
}
};
#else // !BOOST_WORKAROUND(__EDG_VERSION__, <= 300)
template <typename KW, typename DefaultComputer>
struct lazy_default
{
inline BOOST_CONSTEXPR lazy_default(DefaultComputer& x)
: compute_default(x)
{
}
DefaultComputer& compute_default;
};
#endif // EDG workarounds needed.
}}} // namespace boost::parameter::aux
#if BOOST_WORKAROUND(__EDG_VERSION__, <= 300)
#define BOOST_PARAMETER_lazy_default_fallback \
::boost::parameter::aux::lazy_default_base
/**/
#else
#define BOOST_PARAMETER_lazy_default_fallback \
::boost::parameter::aux::lazy_default
/**/
#endif
#if defined(BOOST_PARAMETER_HAS_PERFECT_FORWARDING)
#include <utility>
namespace boost { namespace parameter { namespace aux {
template <typename Keyword, typename Value>
struct default_r_
{
inline BOOST_CONSTEXPR default_r_(Value&& x)
: value(::std::forward<Value>(x))
{
}
Value&& value;
};
}}} // namespace boost::parameter::aux
#endif // BOOST_PARAMETER_HAS_PERFECT_FORWARDING
#endif // include guard
|
