1 | |
2 | #if !defined(BOOST_PP_IS_ITERATING) |
3 | |
4 | ///// header body |
5 | |
6 | #ifndef BOOST_MPL_INHERIT_HPP_INCLUDED |
7 | #define BOOST_MPL_INHERIT_HPP_INCLUDED |
8 | |
9 | // Copyright Aleksey Gurtovoy 2001-2004 |
10 | // |
11 | // Distributed under the Boost Software License, Version 1.0. |
12 | // (See accompanying file LICENSE_1_0.txt or copy at |
13 | // http://www.boost.org/LICENSE_1_0.txt) |
14 | // |
15 | // See http://www.boost.org/libs/mpl for documentation. |
16 | |
17 | // $Id$ |
18 | // $Date$ |
19 | // $Revision$ |
20 | |
21 | #if !defined(BOOST_MPL_PREPROCESSING_MODE) |
22 | # include <boost/mpl/empty_base.hpp> |
23 | # include <boost/mpl/aux_/na_spec.hpp> |
24 | # include <boost/mpl/aux_/lambda_support.hpp> |
25 | #endif |
26 | |
27 | #include <boost/mpl/aux_/config/use_preprocessed.hpp> |
28 | |
29 | #if !defined(BOOST_MPL_CFG_NO_PREPROCESSED_HEADERS) \ |
30 | && !defined(BOOST_MPL_PREPROCESSING_MODE) |
31 | |
32 | # define inherit.hpp |
33 | # include <boost/mpl/aux_/include_preprocessed.hpp> |
34 | |
35 | #else |
36 | |
37 | # include <boost/mpl/limits/arity.hpp> |
38 | # include <boost/mpl/aux_/preprocessor/params.hpp> |
39 | # include <boost/mpl/aux_/preprocessor/default_params.hpp> |
40 | # include <boost/mpl/aux_/preprocessor/enum.hpp> |
41 | # include <boost/mpl/aux_/config/ctps.hpp> |
42 | # include <boost/mpl/aux_/config/dtp.hpp> |
43 | |
44 | # include <boost/preprocessor/iterate.hpp> |
45 | # include <boost/preprocessor/dec.hpp> |
46 | # include <boost/preprocessor/cat.hpp> |
47 | |
48 | namespace boost { namespace mpl { |
49 | |
50 | // 'inherit<T1,T2,..,Tn>' metafunction; returns an unspecified class type |
51 | // produced by public derivation from all metafunction's parameters |
52 | // (T1,T2,..,Tn), except the parameters of 'empty_base' class type; |
53 | // regardless the position and number of 'empty_base' parameters in the |
54 | // metafunction's argument list, derivation from them is always a no-op; |
55 | // for instance: |
56 | // inherit<her>::type == her |
57 | // inherit<her,my>::type == struct unspecified : her, my {}; |
58 | // inherit<empty_base,her>::type == her |
59 | // inherit<empty_base,her,empty_base,empty_base>::type == her |
60 | // inherit<her,empty_base,my>::type == struct unspecified : her, my {}; |
61 | // inherit<empty_base,empty_base>::type == empty_base |
62 | |
63 | #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) |
64 | |
65 | template< |
66 | typename BOOST_MPL_AUX_NA_PARAM(T1) |
67 | , typename BOOST_MPL_AUX_NA_PARAM(T2) |
68 | > |
69 | struct inherit2 |
70 | : T1, T2 |
71 | { |
72 | typedef inherit2 type; |
73 | BOOST_MPL_AUX_LAMBDA_SUPPORT(2, inherit2, (T1,T2)) |
74 | }; |
75 | |
76 | template< typename T1 > |
77 | struct inherit2<T1,empty_base> |
78 | { |
79 | typedef T1 type; |
80 | BOOST_MPL_AUX_LAMBDA_SUPPORT_SPEC(2, inherit2, (T1,empty_base)) |
81 | }; |
82 | |
83 | template< typename T2 > |
84 | struct inherit2<empty_base,T2> |
85 | { |
86 | typedef T2 type; |
87 | BOOST_MPL_AUX_LAMBDA_SUPPORT_SPEC(2, inherit2, (empty_base,T2)) |
88 | }; |
89 | |
90 | // needed to disambiguate the previous two in case when both |
91 | // T1 and T2 == empty_base |
92 | template<> |
93 | struct inherit2<empty_base,empty_base> |
94 | { |
95 | typedef empty_base type; |
96 | BOOST_MPL_AUX_LAMBDA_SUPPORT_SPEC(2, inherit2, (empty_base,empty_base)) |
97 | }; |
98 | |
99 | #else |
100 | |
101 | namespace aux { |
102 | |
103 | template< bool C1, bool C2 > |
104 | struct inherit2_impl |
105 | { |
106 | template< typename Derived, typename T1, typename T2 > struct result_ |
107 | : T1, T2 |
108 | { |
109 | typedef Derived type_; |
110 | }; |
111 | }; |
112 | |
113 | template<> |
114 | struct inherit2_impl<false,true> |
115 | { |
116 | template< typename Derived, typename T1, typename T2 > struct result_ |
117 | : T1 |
118 | { |
119 | typedef T1 type_; |
120 | }; |
121 | }; |
122 | |
123 | template<> |
124 | struct inherit2_impl<true,false> |
125 | { |
126 | template< typename Derived, typename T1, typename T2 > struct result_ |
127 | : T2 |
128 | { |
129 | typedef T2 type_; |
130 | }; |
131 | }; |
132 | |
133 | template<> |
134 | struct inherit2_impl<true,true> |
135 | { |
136 | template< typename Derived, typename T1, typename T2 > struct result_ |
137 | { |
138 | typedef T1 type_; |
139 | }; |
140 | }; |
141 | |
142 | } // namespace aux |
143 | |
144 | template< |
145 | typename BOOST_MPL_AUX_NA_PARAM(T1) |
146 | , typename BOOST_MPL_AUX_NA_PARAM(T2) |
147 | > |
148 | struct inherit2 |
149 | : aux::inherit2_impl< |
150 | is_empty_base<T1>::value |
151 | , is_empty_base<T2>::value |
152 | >::template result_< inherit2<T1,T2>,T1,T2 > |
153 | { |
154 | typedef typename inherit2::type_ type; |
155 | BOOST_MPL_AUX_LAMBDA_SUPPORT(2, inherit2, (T1,T2)) |
156 | }; |
157 | |
158 | #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION |
159 | |
160 | BOOST_MPL_AUX_NA_SPEC(2, inherit2) |
161 | |
162 | #define BOOST_PP_ITERATION_PARAMS_1 \ |
163 | (3,(3, BOOST_MPL_LIMIT_METAFUNCTION_ARITY, <boost/mpl/inherit.hpp>)) |
164 | #include BOOST_PP_ITERATE() |
165 | |
166 | }} |
167 | |
168 | #endif // BOOST_MPL_CFG_NO_PREPROCESSED_HEADERS |
169 | #endif // BOOST_MPL_INHERIT_HPP_INCLUDED |
170 | |
171 | ///// iteration |
172 | |
173 | #else |
174 | #define n_ BOOST_PP_FRAME_ITERATION(1) |
175 | |
176 | template< |
177 | BOOST_MPL_PP_DEFAULT_PARAMS(n_, typename T, na) |
178 | > |
179 | struct BOOST_PP_CAT(inherit,n_) |
180 | : inherit2< |
181 | typename BOOST_PP_CAT(inherit,BOOST_PP_DEC(n_))< |
182 | BOOST_MPL_PP_PARAMS(BOOST_PP_DEC(n_), T) |
183 | >::type |
184 | , BOOST_PP_CAT(T,n_) |
185 | > |
186 | { |
187 | BOOST_MPL_AUX_LAMBDA_SUPPORT( |
188 | n_ |
189 | , BOOST_PP_CAT(inherit,n_) |
190 | , (BOOST_MPL_PP_PARAMS(n_, T)) |
191 | ) |
192 | }; |
193 | |
194 | BOOST_MPL_AUX_NA_SPEC(n_, BOOST_PP_CAT(inherit,n_)) |
195 | |
196 | #if n_ == BOOST_MPL_LIMIT_METAFUNCTION_ARITY |
197 | /// primary template |
198 | template< |
199 | BOOST_MPL_PP_DEFAULT_PARAMS(n_, typename T, empty_base) |
200 | > |
201 | struct inherit |
202 | : BOOST_PP_CAT(inherit,n_)<BOOST_MPL_PP_PARAMS(n_, T)> |
203 | { |
204 | }; |
205 | |
206 | // 'na' specialization |
207 | template<> |
208 | struct inherit< BOOST_MPL_PP_ENUM(5, na) > |
209 | { |
210 | template< |
211 | #if !defined(BOOST_MPL_CFG_NO_DEFAULT_PARAMETERS_IN_NESTED_TEMPLATES) |
212 | BOOST_MPL_PP_DEFAULT_PARAMS(n_, typename T, empty_base) |
213 | #else |
214 | BOOST_MPL_PP_PARAMS(n_, typename T) |
215 | #endif |
216 | > |
217 | struct apply |
218 | : inherit< BOOST_MPL_PP_PARAMS(n_, T) > |
219 | { |
220 | }; |
221 | }; |
222 | |
223 | BOOST_MPL_AUX_NA_SPEC_LAMBDA(n_, inherit) |
224 | BOOST_MPL_AUX_NA_SPEC_ARITY(n_, inherit) |
225 | BOOST_MPL_AUX_NA_SPEC_TEMPLATE_ARITY(n_, n_, inherit) |
226 | #endif |
227 | |
228 | #undef n_ |
229 | #endif // BOOST_PP_IS_ITERATING |
230 | |