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1 | // Boost Lambda Library -- switch.hpp ----------------------------------- |
2 | // | |
3 | // Copyright (C) 2000 Gary Powell (powellg@amazon.com) | |
4 | // Copyright (C) 1999, 2000 Jaakko Jarvi (jaakko.jarvi@cs.utu.fi) | |
5 | // | |
6 | // Distributed under the Boost Software License, Version 1.0. (See | |
7 | // accompanying file LICENSE_1_0.txt or copy at | |
8 | // http://www.boost.org/LICENSE_1_0.txt) | |
9 | // | |
10 | // For more information, see www.boost.org | |
11 | ||
12 | // -------------------------------------------------------------------------- | |
13 | ||
14 | #if !defined(BOOST_LAMBDA_SWITCH_HPP) | |
15 | #define BOOST_LAMBDA_SWITCH_HPP | |
16 | ||
17 | #include "boost/lambda/core.hpp" | |
18 | #include "boost/lambda/detail/control_constructs_common.hpp" | |
19 | ||
20 | #include "boost/preprocessor/enum_shifted_params.hpp" | |
21 | #include "boost/preprocessor/repeat_2nd.hpp" | |
22 | #include "boost/preprocessor/tuple.hpp" | |
23 | ||
24 | namespace boost { | |
25 | namespace lambda { | |
26 | ||
27 | // Switch actions | |
28 | template <int N, class Switch1 = null_type, class Switch2 = null_type, | |
29 | class Switch3 = null_type, class Switch4 = null_type, | |
30 | class Switch5 = null_type, class Switch6 = null_type, | |
31 | class Switch7 = null_type, class Switch8 = null_type, | |
32 | class Switch9 = null_type> | |
33 | struct switch_action {}; | |
34 | ||
35 | ||
36 | namespace detail { | |
37 | ||
38 | // templates to represent special lambda functors for the cases in | |
39 | // switch statements | |
40 | ||
41 | template <int Value> struct case_label {}; | |
42 | struct default_label {}; | |
43 | ||
44 | template<class Type> struct switch_case_tag {}; | |
45 | ||
46 | // a normal case is represented as: | |
47 | // tagged_lambda_functor<switch_case_tag<case_label<N> > >, LambdaFunctor> | |
48 | ||
49 | // the default case as: | |
50 | // tagged_lambda_functor<switch_case_tag<default_label> >, LambdaFunctor> | |
51 | ||
52 | ||
53 | } // end detail | |
54 | ||
55 | ||
56 | /// create switch_case_tag tagged_lambda_functors | |
57 | template <int CaseValue, class Arg> | |
58 | inline const | |
59 | tagged_lambda_functor< | |
60 | detail::switch_case_tag<detail::case_label<CaseValue> >, | |
61 | lambda_functor<Arg> | |
62 | > | |
63 | case_statement(const lambda_functor<Arg>& a) { | |
64 | return | |
65 | tagged_lambda_functor< | |
66 | detail::switch_case_tag<detail::case_label<CaseValue> >, | |
67 | lambda_functor<Arg> | |
68 | >(a); | |
69 | } | |
70 | ||
71 | // No case body case. | |
72 | template <int CaseValue> | |
73 | inline const | |
74 | tagged_lambda_functor< | |
75 | detail::switch_case_tag<detail::case_label<CaseValue> >, | |
76 | lambda_functor< | |
77 | lambda_functor_base< | |
78 | do_nothing_action, | |
79 | null_type | |
80 | > | |
81 | > | |
82 | > | |
83 | case_statement() { | |
84 | return | |
85 | tagged_lambda_functor< | |
86 | detail::switch_case_tag<detail::case_label<CaseValue> >, | |
87 | lambda_functor< | |
88 | lambda_functor_base< | |
89 | do_nothing_action, | |
90 | null_type | |
91 | > | |
92 | > | |
93 | > () ; | |
94 | } | |
95 | ||
96 | // default label | |
97 | template <class Arg> | |
98 | inline const | |
99 | tagged_lambda_functor< | |
100 | detail::switch_case_tag<detail::default_label>, | |
101 | lambda_functor<Arg> | |
102 | > | |
103 | default_statement(const lambda_functor<Arg>& a) { | |
104 | return | |
105 | tagged_lambda_functor< | |
106 | detail::switch_case_tag<detail::default_label>, | |
107 | lambda_functor<Arg> | |
108 | >(a); | |
109 | } | |
110 | ||
111 | // default lable, no case body case. | |
112 | inline const | |
113 | tagged_lambda_functor< | |
114 | detail::switch_case_tag<detail::default_label>, | |
115 | lambda_functor< | |
116 | lambda_functor_base< | |
117 | do_nothing_action, | |
118 | null_type | |
119 | > | |
120 | > | |
121 | > | |
122 | default_statement() { | |
123 | return | |
124 | lambda_functor_base< | |
125 | do_nothing_action, | |
126 | null_type | |
127 | > () ; | |
128 | } | |
129 | ||
130 | ||
131 | // Specializations for lambda_functor_base of case_statement ----------------- | |
132 | ||
133 | // 0 case type: | |
134 | // useless (just the condition part) but provided for completeness. | |
135 | template<class Args> | |
136 | class | |
137 | lambda_functor_base< | |
138 | switch_action<1>, | |
139 | Args | |
140 | > | |
141 | { | |
142 | public: | |
143 | Args args; | |
144 | template <class SigArgs> struct sig { typedef void type; }; | |
145 | public: | |
146 | explicit lambda_functor_base(const Args& a) : args(a) {} | |
147 | ||
148 | template<class RET, CALL_TEMPLATE_ARGS> | |
149 | RET call(CALL_FORMAL_ARGS) const { | |
150 | detail::select(::boost::tuples::get<1>(args), CALL_ACTUAL_ARGS); | |
151 | } | |
152 | }; | |
153 | ||
154 | // 1 case type: | |
155 | // template<class Args, int Case1> | |
156 | // class | |
157 | // lambda_functor_base< | |
158 | // action< | |
159 | // 2, | |
160 | // return_void_action<switch_action<detail::case_label<Case1> > > | |
161 | // >, | |
162 | // Args | |
163 | // > | |
164 | // { | |
165 | // Args args; | |
166 | // public: | |
167 | // explicit lambda_functor_base(const Args& a) : args(a) {} | |
168 | ||
169 | // template<class RET, class A, class B, class C> | |
170 | // RET call(A& a, B& b, C& c) const { | |
171 | // switch( detail::select(::boost::tuples::get<0>(args), a, b, c) ) | |
172 | // { | |
173 | // case Case1: | |
174 | // detail::select(::boost::tuples::get<1>(args), a, b, c); | |
175 | // break; | |
176 | // } | |
177 | // } | |
178 | // }; | |
179 | ||
180 | // switch with default being the sole label - doesn't make much sense but | |
181 | // it is there for completeness | |
182 | // template<class Args> | |
183 | // class | |
184 | // lambda_functor_base< | |
185 | // action< | |
186 | // 2, | |
187 | // return_void_action<switch_action<detail::default_label> > | |
188 | // >, | |
189 | // Args | |
190 | // > | |
191 | // { | |
192 | // Args args; | |
193 | // public: | |
194 | // explicit lambda_functor_base(const Args& a) : args(a) {} | |
195 | // | |
196 | // template<class RET, class A, class B, class C> | |
197 | // RET call(A& a, B& b, C& c) const { | |
198 | // switch( detail::select(::boost::tuples::get<0>(args), a, b, c) ) | |
199 | // { | |
200 | // default: | |
201 | // detail::select(::boost::tuples::get<1>(args), a, b, c); | |
202 | // break; | |
203 | // } | |
204 | // } | |
205 | // }; | |
206 | ||
207 | ||
208 | ||
209 | // // 2 case type: | |
210 | // The different specializations are generated with Vesa Karvonen's | |
211 | // preprocessor library. | |
212 | ||
213 | // This is just a comment to show what the generated classes look like | |
214 | ||
215 | // template<class Args, int Case1, int Case2> | |
216 | // class | |
217 | // lambda_functor_base< | |
218 | // action<3, | |
219 | // return_void_action< | |
220 | // switch_action< | |
221 | // detail::case_label<Case1>, | |
222 | // detail::case_label<Case2> | |
223 | // > | |
224 | // > | |
225 | // >, | |
226 | // Args | |
227 | // > | |
228 | // { | |
229 | // Args args; | |
230 | // public: | |
231 | // explicit lambda_functor_base(const Args& a) : args(a) {} | |
232 | ||
233 | // template<class RET, class A, class B, class C> | |
234 | // RET call(A& a, B& b, C& c) const { | |
235 | // switch( detail::select(::boost::tuples::get<0>(args), a, b, c) ) | |
236 | // { | |
237 | // case Case1: | |
238 | // detail::select(::boost::tuples::get<1>(args), a, b, c); | |
239 | // break; | |
240 | // case Case2: | |
241 | // detail::select(::boost::tuples::get<2>(args), a, b, c); | |
242 | // break; | |
243 | // } | |
244 | // } | |
245 | // }; | |
246 | ||
247 | // template<class Args, int Case1> | |
248 | // class | |
249 | // lambda_functor_base< | |
250 | // action<3, | |
251 | // return_void_action< | |
252 | // switch_action< | |
253 | // detail::case_label<Case1>, | |
254 | // detail::default_label | |
255 | // > | |
256 | // > | |
257 | // >, | |
258 | // Args | |
259 | // > | |
260 | // { | |
261 | // Args args; | |
262 | // public: | |
263 | // explicit lambda_functor_base(const Args& a) : args(a) {} | |
264 | ||
265 | // template<class RET, class A, class B, class C> | |
266 | // RET call(A& a, B& b, C& c) const { | |
267 | // switch( detail::select(::boost::tuples::get<0>(args), a, b, c) ) | |
268 | // { | |
269 | // case Case1: | |
270 | // detail::select(::boost::tuples::get<1>(args), a, b, c); | |
271 | // break; | |
272 | // default: | |
273 | // detail::select(::boost::tuples::get<2>(args), a, b, c); | |
274 | // break; | |
275 | // } | |
276 | // } | |
277 | // }; | |
278 | // ------------------------- | |
279 | ||
280 | // Some helper preprocessor macros --------------------------------- | |
281 | ||
282 | // BOOST_LAMBDA_A_I_LIST(N, X) is a list of form X0, X1, ..., XN | |
283 | // BOOST_LAMBDA_A_I_B_LIST(N, X, Y) is a list of form X0 Y, X1 Y, ..., XN Y | |
284 | ||
285 | #define BOOST_LAMBDA_A_I(z, i, A) \ | |
286 | BOOST_PP_COMMA_IF(i) BOOST_PP_CAT(A,i) | |
287 | ||
288 | #define BOOST_LAMBDA_A_I_B(z, i, T) \ | |
289 | BOOST_PP_COMMA_IF(i) BOOST_PP_CAT(BOOST_PP_TUPLE_ELEM(2,0,T),i) BOOST_PP_TUPLE_ELEM(2,1,T) | |
290 | ||
291 | #define BOOST_LAMBDA_A_I_LIST(i, A) \ | |
292 | BOOST_PP_REPEAT(i,BOOST_LAMBDA_A_I, A) | |
293 | ||
294 | #define BOOST_LAMBDA_A_I_B_LIST(i, A, B) \ | |
295 | BOOST_PP_REPEAT(i,BOOST_LAMBDA_A_I_B, (A,B)) | |
296 | ||
297 | ||
298 | // Switch related macros ------------------------------------------- | |
299 | #define BOOST_LAMBDA_SWITCH_CASE_BLOCK(z, N, A) \ | |
300 | case Case##N: \ | |
301 | detail::select(::boost::tuples::get<BOOST_PP_INC(N)>(args), CALL_ACTUAL_ARGS); \ | |
302 | break; | |
303 | ||
304 | #define BOOST_LAMBDA_SWITCH_CASE_BLOCK_LIST(N) \ | |
305 | BOOST_PP_REPEAT(N, BOOST_LAMBDA_SWITCH_CASE_BLOCK, FOO) | |
306 | // 2 case type: | |
307 | ||
308 | #define BOOST_LAMBDA_SWITCH_NO_DEFAULT_CASE(N) \ | |
309 | template<class Args, BOOST_LAMBDA_A_I_LIST(N, int Case)> \ | |
310 | class \ | |
311 | lambda_functor_base< \ | |
312 | switch_action<BOOST_PP_INC(N), \ | |
313 | BOOST_LAMBDA_A_I_B_LIST(N, detail::case_label<Case,>) \ | |
314 | >, \ | |
315 | Args \ | |
316 | > \ | |
317 | { \ | |
318 | public: \ | |
319 | Args args; \ | |
320 | template <class SigArgs> struct sig { typedef void type; }; \ | |
321 | public: \ | |
322 | explicit lambda_functor_base(const Args& a) : args(a) {} \ | |
323 | \ | |
324 | template<class RET, CALL_TEMPLATE_ARGS> \ | |
325 | RET call(CALL_FORMAL_ARGS) const { \ | |
326 | switch( detail::select(::boost::tuples::get<0>(args), CALL_ACTUAL_ARGS) ) \ | |
327 | { \ | |
328 | BOOST_LAMBDA_SWITCH_CASE_BLOCK_LIST(N) \ | |
329 | } \ | |
330 | } \ | |
331 | }; | |
332 | ||
333 | ||
334 | ||
335 | #define BOOST_LAMBDA_SWITCH_WITH_DEFAULT_CASE(N) \ | |
336 | template< \ | |
337 | class Args BOOST_PP_COMMA_IF(BOOST_PP_DEC(N)) \ | |
338 | BOOST_LAMBDA_A_I_LIST(BOOST_PP_DEC(N), int Case) \ | |
339 | > \ | |
340 | class \ | |
341 | lambda_functor_base< \ | |
342 | switch_action<BOOST_PP_INC(N), \ | |
343 | BOOST_LAMBDA_A_I_B_LIST(BOOST_PP_DEC(N), \ | |
344 | detail::case_label<Case, >) \ | |
345 | BOOST_PP_COMMA_IF(BOOST_PP_DEC(N)) \ | |
346 | detail::default_label \ | |
347 | >, \ | |
348 | Args \ | |
349 | > \ | |
350 | { \ | |
351 | public: \ | |
352 | Args args; \ | |
353 | template <class SigArgs> struct sig { typedef void type; }; \ | |
354 | public: \ | |
355 | explicit lambda_functor_base(const Args& a) : args(a) {} \ | |
356 | \ | |
357 | template<class RET, CALL_TEMPLATE_ARGS> \ | |
358 | RET call(CALL_FORMAL_ARGS) const { \ | |
359 | switch( detail::select(::boost::tuples::get<0>(args), CALL_ACTUAL_ARGS) ) \ | |
360 | { \ | |
361 | BOOST_LAMBDA_SWITCH_CASE_BLOCK_LIST(BOOST_PP_DEC(N)) \ | |
362 | default: \ | |
363 | detail::select(::boost::tuples::get<N>(args), CALL_ACTUAL_ARGS); \ | |
364 | break; \ | |
365 | } \ | |
366 | } \ | |
367 | }; | |
368 | ||
369 | ||
370 | ||
371 | ||
372 | ||
373 | ||
374 | // switch_statement bind functions ------------------------------------- | |
375 | ||
376 | // The zero argument case, for completeness sake | |
377 | inline const | |
378 | lambda_functor< | |
379 | lambda_functor_base< | |
380 | do_nothing_action, | |
381 | null_type | |
382 | > | |
383 | > | |
384 | switch_statement() { | |
385 | return | |
386 | lambda_functor_base< | |
387 | do_nothing_action, | |
388 | null_type | |
389 | > | |
390 | (); | |
391 | } | |
392 | ||
393 | // 1 argument case, this is useless as well, just the condition part | |
394 | template <class TestArg> | |
395 | inline const | |
396 | lambda_functor< | |
397 | lambda_functor_base< | |
398 | switch_action<1>, | |
399 | tuple<lambda_functor<TestArg> > | |
400 | > | |
401 | > | |
402 | switch_statement(const lambda_functor<TestArg>& a1) { | |
403 | return | |
404 | lambda_functor_base< | |
405 | switch_action<1>, | |
406 | tuple< lambda_functor<TestArg> > | |
407 | > | |
408 | ( tuple<lambda_functor<TestArg> >(a1)); | |
409 | } | |
410 | ||
411 | ||
412 | #define HELPER(z, N, FOO) \ | |
413 | BOOST_PP_COMMA_IF(N) \ | |
414 | BOOST_PP_CAT( \ | |
415 | const tagged_lambda_functor<detail::switch_case_tag<TagData, \ | |
416 | N>) \ | |
417 | BOOST_PP_COMMA() Arg##N>& a##N | |
418 | ||
419 | #define HELPER_LIST(N) BOOST_PP_REPEAT(N, HELPER, FOO) | |
420 | ||
421 | ||
422 | #define BOOST_LAMBDA_SWITCH_STATEMENT(N) \ | |
423 | template <class TestArg, \ | |
424 | BOOST_LAMBDA_A_I_LIST(N, class TagData), \ | |
425 | BOOST_LAMBDA_A_I_LIST(N, class Arg)> \ | |
426 | inline const \ | |
427 | lambda_functor< \ | |
428 | lambda_functor_base< \ | |
429 | switch_action<BOOST_PP_INC(N), \ | |
430 | BOOST_LAMBDA_A_I_LIST(N, TagData) \ | |
431 | >, \ | |
432 | tuple<lambda_functor<TestArg>, BOOST_LAMBDA_A_I_LIST(N, Arg)> \ | |
433 | > \ | |
434 | > \ | |
435 | switch_statement( \ | |
436 | const lambda_functor<TestArg>& ta, \ | |
437 | HELPER_LIST(N) \ | |
438 | ) \ | |
439 | { \ | |
440 | return \ | |
441 | lambda_functor_base< \ | |
442 | switch_action<BOOST_PP_INC(N), \ | |
443 | BOOST_LAMBDA_A_I_LIST(N, TagData) \ | |
444 | >, \ | |
445 | tuple<lambda_functor<TestArg>, BOOST_LAMBDA_A_I_LIST(N, Arg)> \ | |
446 | > \ | |
447 | ( tuple<lambda_functor<TestArg>, BOOST_LAMBDA_A_I_LIST(N, Arg)> \ | |
448 | (ta, BOOST_LAMBDA_A_I_LIST(N, a) )); \ | |
449 | } | |
450 | ||
451 | ||
452 | ||
453 | ||
454 | // Here's the actual generation | |
455 | ||
456 | #define BOOST_LAMBDA_SWITCH(N) \ | |
457 | BOOST_LAMBDA_SWITCH_NO_DEFAULT_CASE(N) \ | |
458 | BOOST_LAMBDA_SWITCH_WITH_DEFAULT_CASE(N) | |
459 | ||
460 | // Use this to avoid case 0, these macros work only from case 1 upwards | |
461 | #define BOOST_LAMBDA_SWITCH_HELPER(z, N, A) \ | |
462 | BOOST_LAMBDA_SWITCH( BOOST_PP_INC(N) ) | |
463 | ||
464 | // Use this to avoid cases 0 and 1, these macros work only from case 2 upwards | |
465 | #define BOOST_LAMBDA_SWITCH_STATEMENT_HELPER(z, N, A) \ | |
466 | BOOST_LAMBDA_SWITCH_STATEMENT(BOOST_PP_INC(N)) | |
467 | ||
468 | #ifdef BOOST_MSVC | |
469 | #pragma warning(push) | |
470 | #pragma warning(disable:4065) | |
471 | #endif | |
472 | ||
473 | // up to 9 cases supported (counting default:) | |
474 | BOOST_PP_REPEAT_2ND(9,BOOST_LAMBDA_SWITCH_HELPER,FOO) | |
475 | BOOST_PP_REPEAT_2ND(9,BOOST_LAMBDA_SWITCH_STATEMENT_HELPER,FOO) | |
476 | ||
477 | #ifdef BOOST_MSVC | |
478 | #pragma warning(pop) | |
479 | #endif | |
480 | ||
481 | } // namespace lambda | |
482 | } // namespace boost | |
483 | ||
484 | ||
485 | #undef HELPER | |
486 | #undef HELPER_LIST | |
487 | ||
488 | #undef BOOST_LAMBDA_SWITCH_HELPER | |
489 | #undef BOOST_LAMBDA_SWITCH | |
490 | #undef BOOST_LAMBDA_SWITCH_NO_DEFAULT_CASE | |
491 | #undef BOOST_LAMBDA_SWITCH_WITH_DEFAULT_CASE | |
492 | ||
493 | #undef BOOST_LAMBDA_SWITCH_CASE_BLOCK | |
494 | #undef BOOST_LAMBDA_SWITCH_CASE_BLOCK_LIST | |
495 | ||
496 | #undef BOOST_LAMBDA_SWITCH_STATEMENT | |
497 | #undef BOOST_LAMBDA_SWITCH_STATEMENT_HELPER | |
498 | ||
499 | ||
500 | ||
501 | #endif | |
502 | ||
503 | ||
504 | ||
505 | ||
506 | ||
507 | ||
508 |