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 | |
509 | |