nerdcruft/libcruft-util
1
0
Fork 0
Code Issues Releases Activity

preprocessor: add variadic MAP macro

Browse Source
This commit is contained in:
Danny Robson 2016-03-11 19:15:20 +11:00
parent a59844be98
commit 06739046e0
1 changed files with 51 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

54
preprocessor.hpp
View File

@ -11,16 +11,64 @@
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Copyright 2012 Danny Robson <danny@nerdcruft.net>
* Copyright 2012-2016 Danny Robson <danny@nerdcruft.net>
*/
#ifndef __UTIL_PREPROCESSOR_HPP
#define __UTIL_PREPROCESSOR_HPP
#define PASTE_DETAIL(x, y) x##y
#define PASTE(x, y) PASTE_DETAIL(x, y)
#define STRINGIFY_DETAIL(x) #x
#define STRINGIFY(x) STRINGIFY_DETAIL(x)
#define STRINGIZE_DETAIL(x) #x
#define STRINGIZE(x) STRINGIZE_DETAIL(x)
#define STRINGIZE_LIST(x) STRINGIZE(x),
///////////////////////////////////////////////////////////////////////////////
// Varags functional style map
//
// Based off a technique seen on StackOverflow:
// http://stackoverflow.com/questions/11761703/overloading-macro-on-number-of-arguments
#define MAP_01(F, X) F(X)
#define MAP_02(F, X, ...) F(X)MAP_01(F, __VA_ARGS__)
#define MAP_03(F, X, ...) F(X)MAP_02(F, __VA_ARGS__)
#define MAP_04(F, X, ...) F(X)MAP_03(F, __VA_ARGS__)
#define MAP_05(F, X, ...) F(X)MAP_04(F, __VA_ARGS__)
#define MAP_06(F, X, ...) F(X)MAP_05(F, __VA_ARGS__)
#define MAP_07(F, X, ...) F(X)MAP_06(F, __VA_ARGS__)
#define MAP_08(F, X, ...) F(X)MAP_07(F, __VA_ARGS__)
#define MAP_09(F, X, ...) F(X)MAP_08(F, __VA_ARGS__)
#define MAP_10(F, X, ...) F(X)MAP_09(F, __VA_ARGS__)
#define MAP_11(F, X, ...) F(X)MAP_10(F, __VA_ARGS__)
#define MAP_12(F, X, ...) F(X)MAP_11(F, __VA_ARGS__)
#define MAP_13(F, X, ...) F(X)MAP_12(F, __VA_ARGS__)
#define MAP_14(F, X, ...) F(X)MAP_13(F, __VA_ARGS__)
#define MAP_15(F, X, ...) F(X)MAP_14(F, __VA_ARGS__)
#define MAP_16(F, X, ...) F(X)MAP_15(F, __VA_ARGS__)
// Uses the sliding pairs dispatch technique: by passing __VA_ARGS__ as the
// first set of variables and appending (reverse orderred) names of the
// corresponding macros, we get the name of the correct arity macro.
#define ARITY_DISPATCH( \
_01,_02,_03,_04,_05,_06,_07,_08, \
_09,_10,_11,_12,_13,_14,_15,_16, \
NAME,... \
) NAME
// Map a macro across __VA_ARGS__. Can be easily expanded, but has non-obvious
// failure mode when supported arity is exceeded. Don't use this, unless you
// really need the stringize operator, or other macro magic.
//
// Just use C++ templates. Really...
#define MAP(FUNC,...) \
ARITY_DISPATCH(__VA_ARGS__, \
MAP_16, MAP_15, MAP_14, MAP_13, MAP_12, MAP_11, MAP_10, MAP_09, \
MAP_08, MAP_07, MAP_06, MAP_05, MAP_04, MAP_03, MAP_02, MAP_01 \
)(FUNC, __VA_ARGS__)
#endif