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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 BOOST_MPL_PREPROCESSED_HEADER 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 |