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1 ///////////////////////////////////////////////////////////////////////////////
2 /// \file extends.hpp
3 /// Macros and a base class for defining end-user expression types
4 //
5 //  Copyright 2008 Eric Niebler. Distributed under the Boost
6 //  Software License, Version 1.0. (See accompanying file
7 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
8 
9 #ifndef BOOST_PROTO_EXTENDS_HPP_EAN_11_1_2006
10 #define BOOST_PROTO_EXTENDS_HPP_EAN_11_1_2006
11 
12 #include <cstddef> // for offsetof
13 #include <boost/config.hpp>
14 #include <boost/detail/workaround.hpp>
15 #include <boost/preprocessor/facilities/empty.hpp>
16 #include <boost/preprocessor/tuple/elem.hpp>
17 #include <boost/preprocessor/control/if.hpp>
18 #include <boost/preprocessor/arithmetic/inc.hpp>
19 #include <boost/preprocessor/arithmetic/dec.hpp>
20 #include <boost/preprocessor/iteration/local.hpp>
21 #include <boost/preprocessor/repetition/enum_params.hpp>
22 #include <boost/preprocessor/repetition/repeat_from_to.hpp>
23 #include <boost/preprocessor/repetition/enum_binary_params.hpp>
24 #include <boost/preprocessor/repetition/enum_trailing_params.hpp>
25 #include <boost/preprocessor/repetition/enum_trailing_binary_params.hpp>
26 #include <boost/preprocessor/seq/for_each.hpp>
27 #include <boost/utility/addressof.hpp>
28 #include <boost/utility/result_of.hpp>
29 #include <boost/proto/proto_fwd.hpp>
30 #include <boost/proto/traits.hpp>
31 #include <boost/proto/expr.hpp>
32 #include <boost/proto/args.hpp>
33 #include <boost/proto/traits.hpp>
34 #include <boost/proto/generate.hpp>
35 #include <boost/proto/detail/remove_typename.hpp>
36 
37 #if defined(_MSC_VER)
38 # pragma warning(push)
39 # pragma warning(disable : 4714) // function 'xxx' marked as __forceinline not inlined
40 #endif
41 
42 namespace boost { namespace proto
43 {
44     #ifdef __GNUC__
45     /// INTERNAL ONLY
46     ///
47     # define BOOST_PROTO_ADDROF(x) ((char const volatile*)boost::addressof(x))
48     /// INTERNAL ONLY
49     ///
50     # define BOOST_PROTO_OFFSETOF(s,m) (BOOST_PROTO_ADDROF((((s *)this)->m)) - BOOST_PROTO_ADDROF(*((s *)this)))
51     #else
52     /// INTERNAL ONLY
53     ///
54     # define BOOST_PROTO_OFFSETOF offsetof
55     #endif
56 
57     /// INTERNAL ONLY
58     ///
59     #define BOOST_PROTO_CONST() const
60 
61     /// INTERNAL ONLY
62     ///
63     #define BOOST_PROTO_TYPENAME() typename
64 
65     /// INTERNAL ONLY
66     ///
67     #define BOOST_PROTO_TEMPLATE_YES_(Z, N) template<BOOST_PP_ENUM_PARAMS_Z(Z, N, typename A)>
68 
69     /// INTERNAL ONLY
70     ///
71     #define BOOST_PROTO_TEMPLATE_NO_(Z, N)
72 
73     /// INTERNAL ONLY
74     ///
75     #define BOOST_PROTO_DEFINE_FUN_OP_IMPL_(Z, N, DATA, Const)                                      \
76         BOOST_PP_IF(N, BOOST_PROTO_TEMPLATE_YES_, BOOST_PROTO_TEMPLATE_NO_)(Z, N)                   \
77         BOOST_PROTO_PUSH_WARNINGS                                                                   \
78         BOOST_PROTO_DISABLE_MSVC_C4180                                                              \
79         BOOST_PROTO_DISABLE_MSVC_C4714 BOOST_FORCEINLINE                                            \
80         typename BOOST_PROTO_RESULT_OF<                                                             \
81             proto_generator(                                                                        \
82                 typename boost::proto::result_of::BOOST_PP_CAT(funop, N)<                           \
83                     proto_derived_expr Const()                                                      \
84                   , proto_domain                                                                    \
85                     BOOST_PP_ENUM_TRAILING_PARAMS_Z(Z, N, const A)                                  \
86                 >::type                                                                             \
87             )                                                                                       \
88         >::type const                                                                               \
89         operator ()(BOOST_PP_ENUM_BINARY_PARAMS_Z(Z, N, A, const &a)) Const()                       \
90         {                                                                                           \
91             typedef boost::proto::result_of::BOOST_PP_CAT(funop, N)<                                \
92                 proto_derived_expr Const()                                                          \
93               , proto_domain                                                                        \
94                 BOOST_PP_ENUM_TRAILING_PARAMS_Z(Z, N, const A)                                      \
95             > funop;                                                                                \
96             return proto_generator()(                                                               \
97                 funop::call(                                                                        \
98                     *static_cast<proto_derived_expr Const() *>(this)                                \
99                     BOOST_PP_ENUM_TRAILING_PARAMS_Z(Z, N, a)                                        \
100                 )                                                                                   \
101             );                                                                                      \
102         }                                                                                           \
103         BOOST_PROTO_POP_WARNINGS                                                                    \
104         /**/
105 
106     /// INTERNAL ONLY
107     ///
108     #define BOOST_PROTO_DEFINE_FUN_OP_VARIADIC_IMPL_(Const)                                         \
109         template<typename... A>                                                                     \
110         BOOST_PROTO_PUSH_WARNINGS                                                                   \
111         BOOST_PROTO_DISABLE_MSVC_C4180                                                              \
112         BOOST_PROTO_DISABLE_MSVC_C4714 BOOST_FORCEINLINE                                            \
113         typename BOOST_PROTO_RESULT_OF<                                                             \
114             proto_generator(                                                                        \
115                 typename boost::proto::result_of::funop<                                            \
116                     proto_derived_expr Const()(A const &...)                                        \
117                   , proto_derived_expr                                                              \
118                   , proto_domain                                                                    \
119                 >::type                                                                             \
120             )                                                                                       \
121         >::type const                                                                               \
122         operator ()(A const &...a) Const()                                                          \
123         {                                                                                           \
124             typedef boost::proto::result_of::funop<                                                 \
125                 proto_derived_expr Const()(A const &...)                                            \
126               , proto_derived_expr                                                                  \
127               , proto_domain                                                                        \
128             > funop;                                                                                \
129             return proto_generator()(                                                               \
130                 funop::call(                                                                        \
131                     *static_cast<proto_derived_expr Const() *>(this)                                \
132                   , a...                                                                            \
133                 )                                                                                   \
134             );                                                                                      \
135         }                                                                                           \
136         BOOST_PROTO_POP_WARNINGS                                                                    \
137         /**/
138 
139     /// INTERNAL ONLY
140     ///
141     #define BOOST_PROTO_DEFINE_FUN_OP_CONST(Z, N, DATA)                                             \
142         BOOST_PROTO_DEFINE_FUN_OP_IMPL_(Z, N, DATA, BOOST_PROTO_CONST)                              \
143         /**/
144 
145     /// INTERNAL ONLY
146     ///
147     #define BOOST_PROTO_DEFINE_FUN_OP_NON_CONST(Z, N, DATA)                                         \
148         BOOST_PROTO_DEFINE_FUN_OP_IMPL_(Z, N, DATA, BOOST_PP_EMPTY)                                 \
149         /**/
150 
151     /// INTERNAL ONLY
152     ///
153     #define BOOST_PROTO_DEFINE_FUN_OP(Z, N, DATA)                                                   \
154         BOOST_PROTO_DEFINE_FUN_OP_CONST(Z, N, DATA)                                                 \
155         BOOST_PROTO_DEFINE_FUN_OP_NON_CONST(Z, N, DATA)                                             \
156         /**/
157 
158     /// INTERNAL ONLY
159     ///
160     #define BOOST_PROTO_EXTENDS_CHILD(Z, N, DATA)                                                   \
161         typedef                                                                                     \
162             typename proto_base_expr::BOOST_PP_CAT(proto_child, N)                                  \
163         BOOST_PP_CAT(proto_child, N);                                                               \
164         /**/
165 
166     #define BOOST_PROTO_BASIC_EXTENDS_(Expr, Derived, Domain)                                       \
167         Expr proto_expr_;                                                                           \
168                                                                                                     \
169         typedef Expr proto_base_expr_; /**< INTERNAL ONLY */                                        \
170         typedef typename proto_base_expr_::proto_base_expr proto_base_expr;                         \
171         typedef BOOST_PROTO_REMOVE_TYPENAME(Domain) proto_domain;                                   \
172         typedef Derived proto_derived_expr;                                                         \
173         typedef Domain::proto_generator proto_generator;                                            \
174         typedef typename proto_base_expr::proto_tag proto_tag;                                      \
175         typedef typename proto_base_expr::proto_args proto_args;                                    \
176         typedef typename proto_base_expr::proto_arity proto_arity;                                  \
177         typedef typename proto_base_expr::proto_grammar proto_grammar;                              \
178         typedef typename proto_base_expr::address_of_hack_type_ proto_address_of_hack_type_;        \
179         typedef void proto_is_expr_; /**< INTERNAL ONLY */                                          \
180         static const long proto_arity_c = proto_base_expr::proto_arity_c;                           \
181         typedef boost::proto::tag::proto_expr<proto_tag, proto_domain> fusion_tag;                  \
182         BOOST_PP_REPEAT(BOOST_PROTO_MAX_ARITY, BOOST_PROTO_EXTENDS_CHILD, ~)                        \
183                                                                                                     \
184         BOOST_PROTO_PUSH_WARNINGS                                                                   \
185                                                                                                     \
186         BOOST_PROTO_DISABLE_MSVC_C4714 BOOST_FORCEINLINE                                            \
187         static proto_derived_expr const make(Expr const &e)                                         \
188         {                                                                                           \
189             proto_derived_expr that = {e};                                                          \
190             return that;                                                                            \
191         }                                                                                           \
192                                                                                                     \
193         BOOST_PROTO_DISABLE_MSVC_C4714 BOOST_FORCEINLINE                                            \
194         proto_base_expr &proto_base()                                                               \
195         {                                                                                           \
196             return this->proto_expr_.proto_base();                                                  \
197         }                                                                                           \
198                                                                                                     \
199         BOOST_PROTO_DISABLE_MSVC_C4714 BOOST_FORCEINLINE                                            \
200         proto_base_expr const &proto_base() const                                                   \
201         {                                                                                           \
202             return this->proto_expr_.proto_base();                                                  \
203         }                                                                                           \
204                                                                                                     \
205         BOOST_PROTO_DISABLE_MSVC_C4714 BOOST_FORCEINLINE                                            \
206         operator proto_address_of_hack_type_() const                                                \
207         {                                                                                           \
208             return boost::addressof(this->proto_base().child0);                                     \
209         }                                                                                           \
210                                                                                                     \
211         BOOST_PROTO_POP_WARNINGS                                                                    \
212         /**/
213 
214     #define BOOST_PROTO_BASIC_EXTENDS(Expr, Derived, Domain)                                        \
215         BOOST_PROTO_BASIC_EXTENDS_(Expr, Derived, Domain)                                           \
216         typedef void proto_is_aggregate_;                                                           \
217         /**< INTERNAL ONLY */
218 
219     #define BOOST_PROTO_EXTENDS_COPY_ASSIGN_IMPL_(This, Const, Typename)                            \
220         BOOST_PROTO_PUSH_WARNINGS                                                                   \
221         BOOST_PROTO_DISABLE_MSVC_C4522                                                              \
222         BOOST_PROTO_DISABLE_MSVC_C4714 BOOST_FORCEINLINE                                            \
223         Typename() BOOST_PROTO_RESULT_OF<                                                           \
224             Typename() This::proto_generator(                                                       \
225                 Typename() boost::proto::base_expr<                                                 \
226                     Typename() This::proto_domain                                                   \
227                   , boost::proto::tag::assign                                                       \
228                   , boost::proto::list2<                                                            \
229                         This &                                                                      \
230                       , This Const() &                                                              \
231                     >                                                                               \
232                 >::type                                                                             \
233             )                                                                                       \
234         >::type const                                                                               \
235         operator =(This Const() &a)                                                                 \
236         {                                                                                           \
237             typedef                                                                                 \
238                 Typename() boost::proto::base_expr<                                                 \
239                     Typename() This::proto_domain                                                   \
240                   , boost::proto::tag::assign                                                       \
241                   , boost::proto::list2<                                                            \
242                         This &                                                                      \
243                       , This Const() &                                                              \
244                     >                                                                               \
245                 >::type                                                                             \
246             that_type;                                                                              \
247             that_type const that = {                                                                \
248                 *this                                                                               \
249               , a                                                                                   \
250             };                                                                                      \
251             return Typename() This::proto_generator()(that);                                        \
252         }                                                                                           \
253         BOOST_PROTO_POP_WARNINGS                                                                    \
254         /**/
255 
256         // MSVC 8.0 and higher seem to need copy-assignment operator to be overloaded on *both*
257         // const and non-const rhs arguments.
258     #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1600)) && (BOOST_MSVC > 1310)
259         #define BOOST_PROTO_EXTENDS_COPY_ASSIGN_(This, Typename)                                    \
260             BOOST_PROTO_EXTENDS_COPY_ASSIGN_IMPL_(This, BOOST_PP_EMPTY, Typename)                   \
261             BOOST_PROTO_EXTENDS_COPY_ASSIGN_IMPL_(This, BOOST_PROTO_CONST, Typename)                \
262             /**/
263     #else
264         #define BOOST_PROTO_EXTENDS_COPY_ASSIGN_(This, Typename)                                    \
265             BOOST_PROTO_EXTENDS_COPY_ASSIGN_IMPL_(This, BOOST_PROTO_CONST, Typename)                \
266             /**/
267     #endif
268 
269         /// INTERNAL ONLY
270         ///
271     #define BOOST_PROTO_EXTENDS_ASSIGN_IMPL_(ThisConst, ThatConst)                                  \
272         template<typename A>                                                                        \
273         BOOST_PROTO_PUSH_WARNINGS                                                                   \
274         BOOST_PROTO_DISABLE_MSVC_C4180                                                              \
275         BOOST_PROTO_DISABLE_MSVC_C4714 BOOST_FORCEINLINE                                            \
276         typename BOOST_PROTO_RESULT_OF<                                                             \
277             proto_generator(                                                                        \
278                 typename boost::proto::base_expr<                                                   \
279                     proto_domain                                                                    \
280                   , boost::proto::tag::assign                                                       \
281                   , boost::proto::list2<                                                            \
282                         proto_derived_expr ThisConst() &                                            \
283                       , typename boost::proto::result_of::as_child<A ThatConst(), proto_domain>::type \
284                     >                                                                               \
285                 >::type                                                                             \
286             )                                                                                       \
287         >::type const                                                                               \
288         operator =(A ThatConst() &a) ThisConst()                                                    \
289         {                                                                                           \
290             typedef                                                                                 \
291                 typename boost::proto::base_expr<                                                   \
292                     proto_domain                                                                    \
293                   , boost::proto::tag::assign                                                       \
294                   , boost::proto::list2<                                                            \
295                         proto_derived_expr ThisConst() &                                            \
296                       , typename boost::proto::result_of::as_child<A ThatConst(), proto_domain>::type \
297                     >                                                                               \
298                 >::type                                                                             \
299             that_type;                                                                              \
300             that_type const that = {                                                                \
301                 *static_cast<proto_derived_expr ThisConst() *>(this)                                \
302               , boost::proto::as_child<proto_domain>(a)                                             \
303             };                                                                                      \
304             return proto_generator()(that);                                                         \
305         }                                                                                           \
306         BOOST_PROTO_POP_WARNINGS                                                                    \
307         /**/
308 
309     #define BOOST_PROTO_EXTENDS_ASSIGN_CONST_()                                                     \
310         BOOST_PROTO_EXTENDS_ASSIGN_IMPL_(BOOST_PROTO_CONST, BOOST_PP_EMPTY)                         \
311         BOOST_PROTO_EXTENDS_ASSIGN_IMPL_(BOOST_PROTO_CONST, BOOST_PROTO_CONST)                      \
312         /**/
313 
314     #define BOOST_PROTO_EXTENDS_ASSIGN_NON_CONST_()                                                 \
315         BOOST_PROTO_EXTENDS_ASSIGN_IMPL_(BOOST_PP_EMPTY, BOOST_PP_EMPTY)                            \
316         BOOST_PROTO_EXTENDS_ASSIGN_IMPL_(BOOST_PP_EMPTY, BOOST_PROTO_CONST)                         \
317         /**/
318 
319     #define BOOST_PROTO_EXTENDS_ASSIGN_()                                                           \
320         BOOST_PROTO_EXTENDS_ASSIGN_CONST_()                                                         \
321         BOOST_PROTO_EXTENDS_ASSIGN_NON_CONST_()                                                     \
322         /**/
323 
324     #define BOOST_PROTO_EXTENDS_ASSIGN_CONST()                                                      \
325         BOOST_PROTO_EXTENDS_COPY_ASSIGN_(proto_derived_expr, BOOST_PROTO_TYPENAME)                  \
326         BOOST_PROTO_EXTENDS_ASSIGN_CONST_()                                                         \
327         /**/
328 
329     #define BOOST_PROTO_EXTENDS_ASSIGN_NON_CONST()                                                  \
330         BOOST_PROTO_EXTENDS_COPY_ASSIGN_(proto_derived_expr, BOOST_PROTO_TYPENAME)                  \
331         BOOST_PROTO_EXTENDS_ASSIGN_NON_CONST_()                                                     \
332         /**/
333 
334     #define BOOST_PROTO_EXTENDS_ASSIGN()                                                            \
335         BOOST_PROTO_EXTENDS_COPY_ASSIGN_(proto_derived_expr, BOOST_PROTO_TYPENAME)                  \
336         BOOST_PROTO_EXTENDS_ASSIGN_()                                                               \
337         /**/
338 
339         /// INTERNAL ONLY
340         ///
341     #define BOOST_PROTO_EXTENDS_SUBSCRIPT_IMPL_(ThisConst, ThatConst)                               \
342         template<typename A>                                                                        \
343         BOOST_PROTO_PUSH_WARNINGS                                                                   \
344         BOOST_PROTO_DISABLE_MSVC_C4180                                                              \
345         BOOST_PROTO_DISABLE_MSVC_C4714 BOOST_FORCEINLINE                                            \
346         typename BOOST_PROTO_RESULT_OF<                                                             \
347             proto_generator(                                                                        \
348                 typename boost::proto::base_expr<                                                   \
349                     proto_domain                                                                    \
350                   , boost::proto::tag::subscript                                                    \
351                   , boost::proto::list2<                                                            \
352                         proto_derived_expr ThisConst() &                                            \
353                       , typename boost::proto::result_of::as_child<A ThatConst(), proto_domain>::type \
354                     >                                                                               \
355                 >::type                                                                             \
356             )                                                                                       \
357         >::type const                                                                               \
358         operator [](A ThatConst() &a) ThisConst()                                                   \
359         {                                                                                           \
360             typedef                                                                                 \
361                 typename boost::proto::base_expr<                                                   \
362                     proto_domain                                                                    \
363                   , boost::proto::tag::subscript                                                    \
364                   , boost::proto::list2<                                                            \
365                         proto_derived_expr ThisConst() &                                            \
366                       , typename boost::proto::result_of::as_child<A ThatConst(), proto_domain>::type \
367                     >                                                                               \
368                 >::type                                                                             \
369             that_type;                                                                              \
370             that_type const that = {                                                                \
371                 *static_cast<proto_derived_expr ThisConst() *>(this)                                \
372               , boost::proto::as_child<proto_domain>(a)                                             \
373             };                                                                                      \
374             return proto_generator()(that);                                                         \
375         }                                                                                           \
376         BOOST_PROTO_POP_WARNINGS                                                                    \
377         /**/
378 
379     #define BOOST_PROTO_EXTENDS_SUBSCRIPT_CONST()                                                   \
380         BOOST_PROTO_EXTENDS_SUBSCRIPT_IMPL_(BOOST_PROTO_CONST, BOOST_PP_EMPTY)                      \
381         BOOST_PROTO_EXTENDS_SUBSCRIPT_IMPL_(BOOST_PROTO_CONST, BOOST_PROTO_CONST)                   \
382         /**/
383 
384     #define BOOST_PROTO_EXTENDS_SUBSCRIPT_NON_CONST()                                               \
385         BOOST_PROTO_EXTENDS_SUBSCRIPT_IMPL_(BOOST_PP_EMPTY, BOOST_PP_EMPTY)                         \
386         BOOST_PROTO_EXTENDS_SUBSCRIPT_IMPL_(BOOST_PP_EMPTY, BOOST_PROTO_CONST)                      \
387         /**/
388 
389     #define BOOST_PROTO_EXTENDS_SUBSCRIPT()                                                         \
390         BOOST_PROTO_EXTENDS_SUBSCRIPT_CONST()                                                       \
391         BOOST_PROTO_EXTENDS_SUBSCRIPT_NON_CONST()                                                   \
392         /**/
393 
394         /// INTERNAL ONLY
395         ///
396     #define BOOST_PROTO_EXTENDS_FUNCTION_()                                                         \
397         template<typename Sig>                                                                      \
398         struct result                                                                               \
399         {                                                                                           \
400             typedef                                                                                 \
401                 typename BOOST_PROTO_RESULT_OF<                                                     \
402                     proto_generator(                                                                \
403                         typename boost::proto::result_of::funop<                                    \
404                             Sig                                                                     \
405                           , proto_derived_expr                                                      \
406                           , proto_domain                                                            \
407                         >::type                                                                     \
408                     )                                                                               \
409                 >::type const                                                                       \
410             type;                                                                                   \
411         };                                                                                          \
412         /**/
413 
414     #ifndef BOOST_NO_CXX11_VARIADIC_TEMPLATES
415         #define BOOST_PROTO_EXTENDS_FUNCTION_CONST()                                                \
416             BOOST_PROTO_EXTENDS_FUNCTION_()                                                         \
417             BOOST_PROTO_DEFINE_FUN_OP_VARIADIC_IMPL_(BOOST_PROTO_CONST)                             \
418             /**/
419 
420         #define BOOST_PROTO_EXTENDS_FUNCTION_NON_CONST()                                            \
421             BOOST_PROTO_EXTENDS_FUNCTION_()                                                         \
422             BOOST_PROTO_DEFINE_FUN_OP_VARIADIC_IMPL_(BOOST_PP_EMPTY)                                \
423             /**/
424 
425         #define BOOST_PROTO_EXTENDS_FUNCTION()                                                      \
426             BOOST_PROTO_EXTENDS_FUNCTION_()                                                         \
427             BOOST_PROTO_DEFINE_FUN_OP_VARIADIC_IMPL_(BOOST_PP_EMPTY)                                \
428             BOOST_PROTO_DEFINE_FUN_OP_VARIADIC_IMPL_(BOOST_PROTO_CONST)                             \
429             /**/
430     #else
431         #define BOOST_PROTO_EXTENDS_FUNCTION_CONST()                                                \
432             BOOST_PROTO_EXTENDS_FUNCTION_()                                                         \
433             BOOST_PP_REPEAT_FROM_TO(                                                                \
434                 0                                                                                   \
435               , BOOST_PROTO_MAX_FUNCTION_CALL_ARITY                                                 \
436               , BOOST_PROTO_DEFINE_FUN_OP_CONST                                                     \
437               , ~                                                                                   \
438             )                                                                                       \
439             /**/
440 
441         #define BOOST_PROTO_EXTENDS_FUNCTION_NON_CONST()                                            \
442             BOOST_PROTO_EXTENDS_FUNCTION_()                                                         \
443             BOOST_PP_REPEAT_FROM_TO(                                                                \
444                 0                                                                                   \
445               , BOOST_PROTO_MAX_FUNCTION_CALL_ARITY                                                 \
446               , BOOST_PROTO_DEFINE_FUN_OP_NON_CONST                                                 \
447               , ~                                                                                   \
448             )                                                                                       \
449             /**/
450 
451         #define BOOST_PROTO_EXTENDS_FUNCTION()                                                      \
452             BOOST_PROTO_EXTENDS_FUNCTION_()                                                         \
453             BOOST_PP_REPEAT_FROM_TO(                                                                \
454                 0                                                                                   \
455               , BOOST_PROTO_MAX_FUNCTION_CALL_ARITY                                                 \
456               , BOOST_PROTO_DEFINE_FUN_OP                                                           \
457               , ~                                                                                   \
458             )                                                                                       \
459             /**/
460     #endif
461 
462     #define BOOST_PROTO_EXTENDS(Expr, Derived, Domain)                                              \
463         BOOST_PROTO_BASIC_EXTENDS(Expr, Derived, Domain)                                            \
464         BOOST_PROTO_EXTENDS_ASSIGN()                                                                \
465         BOOST_PROTO_EXTENDS_SUBSCRIPT()                                                             \
466         BOOST_PROTO_EXTENDS_FUNCTION()                                                              \
467         /**/
468 
469     #define BOOST_PROTO_EXTENDS_USING_ASSIGN(Derived)                                               \
470         typedef typename Derived::proto_extends proto_extends;                                      \
471         using proto_extends::operator =;                                                            \
472         BOOST_PROTO_EXTENDS_COPY_ASSIGN_(Derived, BOOST_PROTO_TYPENAME)                             \
473         /**/
474 
475     #define BOOST_PROTO_EXTENDS_USING_ASSIGN_NON_DEPENDENT(Derived)                                 \
476         typedef Derived::proto_extends proto_extends;                                               \
477         using proto_extends::operator =;                                                            \
478         BOOST_PROTO_EXTENDS_COPY_ASSIGN_(Derived, BOOST_PP_EMPTY)                                   \
479         /**/
480 
481     namespace exprns_
482     {
483         /// \brief Empty type to be used as a dummy template parameter of
484         ///     POD expression wrappers. It allows argument-dependent lookup
485         ///     to find Proto's operator overloads.
486         ///
487         /// \c proto::is_proto_expr allows argument-dependent lookup
488         ///     to find Proto's operator overloads. For example:
489         ///
490         /// \code
491         /// template<typename T, typename Dummy = proto::is_proto_expr>
492         /// struct my_terminal
493         /// {
494         ///     BOOST_PROTO_BASIC_EXTENDS(
495         ///         typename proto::terminal<T>::type
496         ///       , my_terminal<T>
497         ///       , default_domain
498         ///     )
499         /// };
500         ///
501         /// // ...
502         /// my_terminal<int> _1, _2;
503         /// _1 + _2; // OK, uses proto::operator+
504         /// \endcode
505         ///
506         /// Without the second \c Dummy template parameter, Proto's operator
507         /// overloads would not be considered by name lookup.
508         struct is_proto_expr
509         {};
510 
511         /// \brief extends\<\> class template for adding behaviors to a Proto expression template
512         ///
513         template<
514             typename Expr
515           , typename Derived
516           , typename Domain     // = proto::default_domain
517           , long Arity          // = Expr::proto_arity_c
518         >
519         struct extends
520         {
521             BOOST_FORCEINLINE
extendsboost::proto::exprns_::extends522             extends()
523               : proto_expr_()
524             {}
525 
526             BOOST_FORCEINLINE
extendsboost::proto::exprns_::extends527             extends(Expr const &expr_)
528               : proto_expr_(expr_)
529             {}
530 
531             typedef extends proto_extends;
532             BOOST_PROTO_BASIC_EXTENDS_(Expr, Derived, typename Domain)
533             BOOST_PROTO_EXTENDS_ASSIGN_CONST_()
534             BOOST_PROTO_EXTENDS_SUBSCRIPT_CONST()
535 
536             // Instead of using BOOST_PROTO_EXTENDS_FUNCTION, which uses
537             // nested preprocessor loops, use file iteration here to generate
538             // the operator() overloads, which is more efficient.
539             #include <boost/proto/detail/extends_funop_const.hpp>
540         };
541 
542         /// \brief extends\<\> class template for adding behaviors to a Proto expression template
543         ///
544         template<typename Expr, typename Derived, typename Domain>
545         struct extends<Expr, Derived, Domain, 0>
546         {
547             BOOST_FORCEINLINE
extendsboost::proto::exprns_::extends548             extends()
549               : proto_expr_()
550             {}
551 
552             BOOST_FORCEINLINE
extendsboost::proto::exprns_::extends553             extends(Expr const &expr_)
554               : proto_expr_(expr_)
555             {}
556 
557             typedef extends proto_extends;
558             BOOST_PROTO_BASIC_EXTENDS_(Expr, Derived, typename Domain)
559             BOOST_PROTO_EXTENDS_ASSIGN_()
560             BOOST_PROTO_EXTENDS_SUBSCRIPT()
561 
562             // Instead of using BOOST_PROTO_EXTENDS_FUNCTION, which uses
563             // nested preprocessor loops, use file iteration here to generate
564             // the operator() overloads, which is more efficient.
565             #include <boost/proto/detail/extends_funop.hpp>
566         };
567 
568         /// INTERNAL ONLY
569         ///
570         template<typename This, typename Fun, typename Domain>
571         struct virtual_member
572         {
573             typedef Domain proto_domain;
574             typedef typename Domain::proto_generator proto_generator;
575             typedef virtual_member<This, Fun, Domain> proto_derived_expr;
576             typedef tag::member proto_tag;
577             typedef list2<This &, expr<tag::terminal, term<Fun> > const &> proto_args;
578             typedef mpl::long_<2> proto_arity;
579             typedef detail::not_a_valid_type proto_address_of_hack_type_;
580             typedef void proto_is_expr_; /**< INTERNAL ONLY */
581             static const long proto_arity_c = 2;
582             typedef boost::proto::tag::proto_expr<proto_tag, Domain> fusion_tag;
583             typedef This &proto_child0;
584             typedef expr<tag::terminal, term<Fun> > const &proto_child1;
585             typedef expr<proto_tag, proto_args, proto_arity_c> proto_base_expr;
586             typedef basic_expr<proto_tag, proto_args, proto_arity_c> proto_grammar;
587             typedef void proto_is_aggregate_; /**< INTERNAL ONLY */
588 
589             BOOST_PROTO_EXTENDS_ASSIGN_()
BOOST_PROTO_EXTENDS_SUBSCRIPTboost::proto::exprns_::virtual_member590             BOOST_PROTO_EXTENDS_SUBSCRIPT()
591 
592             // Instead of using BOOST_PROTO_EXTENDS_FUNCTION, which uses
593             // nested preprocessor loops, use file iteration here to generate
594             // the operator() overloads, which is more efficient.
595             #define BOOST_PROTO_NO_WAVE_OUTPUT
596             #include <boost/proto/detail/extends_funop.hpp>
597             #undef BOOST_PROTO_NO_WAVE_OUTPUT
598 
599             BOOST_FORCEINLINE
600             proto_base_expr const proto_base() const
601             {
602                 proto_base_expr that = {this->child0(), this->child1()};
603                 return that;
604             }
605 
606             BOOST_FORCEINLINE
child0boost::proto::exprns_::virtual_member607             proto_child0 child0() const
608             {
609                 using std::size_t;
610                 return *(This *)((char *)this - BOOST_PROTO_OFFSETOF(This, proto_member_union_start_));
611             }
612 
613             BOOST_FORCEINLINE
child1boost::proto::exprns_::virtual_member614             proto_child1 child1() const
615             {
616                 static expr<tag::terminal, term<Fun>, 0> const that = {Fun()};
617                 return that;
618             }
619         };
620 
621         /// INTERNAL ONLY
622         ///
623         #define BOOST_PROTO_EXTENDS_MEMBER_(R, DOMAIN, ELEM)                                            \
624             boost::proto::exprns_::virtual_member<                                                      \
625                 proto_derived_expr                                                                      \
626               , BOOST_PP_TUPLE_ELEM(2, 0, ELEM)                                                         \
627               , DOMAIN                                                                                  \
628             > BOOST_PP_TUPLE_ELEM(2, 1, ELEM);                                                          \
629             /**/
630 
631         /// \brief For declaring virtual data members in an extension class.
632         ///
633         #define BOOST_PROTO_EXTENDS_MEMBERS_WITH_DOMAIN(SEQ, DOMAIN)                                    \
634             union                                                                                       \
635             {                                                                                           \
636                 char proto_member_union_start_;                                                         \
637                 BOOST_PP_SEQ_FOR_EACH(BOOST_PROTO_EXTENDS_MEMBER_, DOMAIN, SEQ)                         \
638             };                                                                                          \
639             /**/
640 
641         /// \brief For declaring virtual data members in an extension class.
642         ///
643         #define BOOST_PROTO_EXTENDS_MEMBERS(SEQ)                                                        \
644             BOOST_PROTO_EXTENDS_MEMBERS_WITH_DOMAIN(SEQ, proto_domain)                                  \
645             /**/
646 
647     }
648 
649 }}
650 
651 #if defined(_MSC_VER)
652 # pragma warning(pop)
653 #endif
654 
655 #endif
656