summaryrefslogtreecommitdiffstats
blob: 2bde53bda91a4aee37971bb405f59deb22a0e375 (plain)
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
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
///////////////////////////////////////////////////////////////////////////////
/// \file poly_function.hpp
/// A wrapper that makes a tr1-style function object that handles const
/// and non-const refs and reference_wrapper arguments, too, and forwards
/// the arguments on to the specified implementation.
//
//  Copyright 2008 Eric Niebler. 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 BOOST_PROTO_DETAIL_POLY_FUNCTION_EAN_2008_05_02
#define BOOST_PROTO_DETAIL_POLY_FUNCTION_EAN_2008_05_02

#include <boost/ref.hpp>
#include <boost/mpl/bool.hpp>
#include <boost/mpl/void.hpp>
#include <boost/mpl/size_t.hpp>
#include <boost/mpl/eval_if.hpp>
#include <boost/preprocessor/cat.hpp>
#include <boost/preprocessor/facilities/intercept.hpp>
#include <boost/preprocessor/iteration/iterate.hpp>
#include <boost/preprocessor/repetition/enum.hpp>
#include <boost/preprocessor/repetition/enum_params.hpp>
#include <boost/preprocessor/repetition/enum_trailing_params.hpp>
#include <boost/preprocessor/repetition/enum_binary_params.hpp>
#include <boost/proto/proto_fwd.hpp>
#include <boost/proto/detail/is_noncopyable.hpp>

#ifdef _MSC_VER
# pragma warning(push)
# pragma warning(disable: 4181) // const applied to reference type
#endif

namespace boost { namespace proto { namespace detail
{

    ////////////////////////////////////////////////////////////////////////////////////////////////
    template<typename T>
    struct normalize_arg
    {
        typedef typename mpl::if_c<is_noncopyable<T>::value, T &, T>::type type;
        typedef T &reference;
    };

    template<typename T>
    struct normalize_arg<T const>
    {
        typedef typename mpl::if_c<is_noncopyable<T>::value, T const &, T>::type type;
        typedef T const &reference;
    };

    template<typename T>
    struct normalize_arg<T &>
    {
        typedef typename mpl::if_c<is_noncopyable<T>::value, T &, T>::type type;
        typedef T &reference;
    };

    template<typename T>
    struct normalize_arg<T const &>
    {
        typedef typename mpl::if_c<is_noncopyable<T>::value, T const &, T>::type type;
        typedef T const &reference;
    };

    template<typename T>
    struct normalize_arg<boost::reference_wrapper<T> >
    {
        typedef T &type;
        typedef T &reference;
    };

    template<typename T>
    struct normalize_arg<boost::reference_wrapper<T> const>
    {
        typedef T &type;
        typedef T &reference;
    };

    template<typename T>
    struct normalize_arg<boost::reference_wrapper<T> &>
    {
        typedef T &type;
        typedef T &reference;
    };

    template<typename T>
    struct normalize_arg<boost::reference_wrapper<T> const &>
    {
        typedef T &type;
        typedef T &reference;
    };

    ////////////////////////////////////////////////////////////////////////////////////////////////
    template<typename T>
    struct arg
    {
        typedef T const &type;

        arg(type t)
          : value(t)
        {}

        operator type() const
        {
            return this->value;
        }

        type operator()() const
        {
            return this->value;
        }

    private:
        arg &operator =(arg const &);
        type value;
    };

    template<typename T>
    struct arg<T &>
    {
        typedef T &type;

        arg(type t)
          : value(t)
        {}

        operator type() const
        {
            return this->value;
        }

        type operator()() const
        {
            return this->value;
        }

    private:
        arg &operator =(arg const &);
        type value;
    };

    ////////////////////////////////////////////////////////////////////////////////////////////////
    template<typename T, typename Void = void>
    struct is_poly_function
      : mpl::false_
    {};

    template<typename T>
    struct is_poly_function<T, typename T::is_poly_function_base_>
      : mpl::true_
    {};

    ////////////////////////////////////////////////////////////////////////////////////////////////
    #define BOOST_PROTO_POLY_FUNCTION()                                                             \
        typedef void is_poly_function_base_;                                                        \
        /**/

    ////////////////////////////////////////////////////////////////////////////////////////////////
    struct poly_function_base
    {
        /// INTERNAL ONLY
        BOOST_PROTO_POLY_FUNCTION()
    };

    ////////////////////////////////////////////////////////////////////////////////////////////////
    template<typename Derived, typename NullaryResult = void>
    struct poly_function
      : poly_function_base
    {
        template<typename Sig>
        struct result;

        template<typename This>
        struct result<This()>
          : Derived::template impl<>
        {
            typedef typename result::result_type type;
        };

        NullaryResult operator()() const
        {
            result<Derived const()> impl;
            return impl();
        }

        #include <boost/proto/detail/poly_function_funop.hpp>
    };

    template<typename T>
    struct wrap_t;

    typedef char poly_function_t;
    typedef char (&mono_function_t)[2];
    typedef char (&unknown_function_t)[3];

    template<typename T> poly_function_t test_poly_function(T *, wrap_t<typename T::is_poly_function_base_> * = 0);
    template<typename T> mono_function_t test_poly_function(T *, wrap_t<typename T::result_type> * = 0);
    template<typename T> unknown_function_t test_poly_function(T *, ...);

    ////////////////////////////////////////////////////////////////////////////////////////////////
    template<typename Fun, typename Sig, typename Switch = mpl::size_t<sizeof(test_poly_function<Fun>(0,0))> >
    struct poly_function_traits
    {
        typedef typename Fun::template result<Sig>::type result_type;
        typedef Fun function_type;
    };

    ////////////////////////////////////////////////////////////////////////////////////////////////
    template<typename Fun, typename Sig>
    struct poly_function_traits<Fun, Sig, mpl::size_t<sizeof(mono_function_t)> >
    {
        typedef typename Fun::result_type result_type;
        typedef Fun function_type;
    };

    ////////////////////////////////////////////////////////////////////////////////////////////////
    template<typename PolyFunSig, bool IsPolyFunction>
    struct as_mono_function_impl;

    ////////////////////////////////////////////////////////////////////////////////////////////////
    template<typename PolyFunSig>
    struct as_mono_function;

    #include <boost/proto/detail/poly_function_traits.hpp>

}}} // namespace boost::proto::detail

#ifdef _MSC_VER
# pragma warning(pop)
#endif

#endif