so true

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          數據加載中……

          使用boost的preprocessor

          在線文檔:http://www.boost.org/doc/libs/1_48_0/libs/preprocessor/doc/index.html
                        http://www.boost.org/doc/libs/1_48_0/libs/preprocessor/doc/topics/techniques.html
                        http://www.boost.org/doc/libs/1_48_0/libs/preprocessor/doc/ref.html
          幾篇不錯的博文:http://blog.csdn.net/zx77/article/details/2270991
          一個關于2D的repeat的實現 :
          /* Copyright (C) 2002
           * Housemarque Oy
           * http://www.housemarque.com
           *
           * Permission to copy, use, modify, sell and distribute this software is
           * granted provided this copyright notice appears in all copies. This
           * software is provided "as is" without express or implied warranty, and
           * with no claim as to its suitability for any purpose.
           *
           * See http://www.boost.org for most recent version.
           */

          /* This example implements a generalized macro for 2D repetition using
           * the simple repetition primitives of the preprocessor library.
           */

          #include "preprocessor/repeat.hpp"
          #include "preprocessor/logical/or.hpp"
          #include "preprocessor/comma_if.hpp"
          #include "preprocessor/list/cat.hpp"
          #include "preprocessor/tuple/elem.hpp"
          #include "preprocessor/tuple/to_list.hpp"

          /** <p>Repeats the macro <code>M(X,Y,DATA)</code> for <code>X = [0,W)</code> and <code>Y = [0,H)</code>.</p>

          <p>In other words, expands to the sequence:</p>

          <pre>
          M(  0,  0,  DATA) M(  1,  0,  DATA) ... M(W-1,  0,  DATA)
          M(  0,  1,  DATA) M(  1,  1,  DATA) ... M(W-1,  1,  DATA)
                ...            ...      ...       ...
          M(  0,H-1,  DATA) M(  1,H-1,  DATA) ... M(W-1,H-1,  DATA)
          </pre>
          */
          #define REPEAT_2D(W,H,M,DATA)\
            /* Here we can simply use BOOST_PP_REPEAT(), because\
             * it implements automatic recursion.\
             */\
            BOOST_PP_REPEAT\
            ( H\
            , REPEAT_2D_ROW\
            , (W,M,DATA)\
            )
          #define REPEAT_2D_ROW(z,Y,WMD)\
            BOOST_PP_REPEAT\
            ( BOOST_PP_TUPLE_ELEM(3,0,WMD)\
            , REPEAT_2D_ELEM\
            , (Y, BOOST_PP_TUPLE_ELEM(3,1,WMD), BOOST_PP_TUPLE_ELEM(3,2,WMD))\
            )
          #define REPEAT_2D_ELEM(z,X,YMD)\
            BOOST_PP_TUPLE_ELEM(3,1,YMD)\
            ( X\
            , BOOST_PP_TUPLE_ELEM(3,0,YMD)\
            , BOOST_PP_TUPLE_ELEM(3,2,YMD)\
            )

          /* Here we use the above macro to generate something. */
          #define ELEM(X,Y,E) BOOST_PP_COMMA_IF(BOOST_PP_OR(X,Y)) BOOST_PP_LIST_CAT(BOOST_PP_TUPLE_TO_LIST(5,(E,_,X,_,Y)))
          enum { REPEAT_2D(3,4,ELEM,elem) };

          /* The above expands to:
           *
           * enum { elem_0_0, elem_1_0, elem_2_0,
           *        elem_0_1, elem_1_1, elem_2_1,
           *        elem_0_2, elem_1_2, elem_2_2,
           *        elem_0_3, elem_1_3, elem_2_3 };
           */

          posted on 2011-11-26 14:10 so true 閱讀(945) 評論(0)  編輯  收藏 所屬分類: C&C++

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