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  1. // マクロ
  2. string makeHANDLE_MSG(alias hwnd, alias message, string fn)() @property
  3. { 
  4.     return "case " ~ message.stringof ~ ":"
  5.             "return HANDLE_" ~ message.stringof ~ "("
  6.                 ~ hwnd.stringof ~ ", wParam, lParam, "
  7.                 ~ "&" ~ fn ~ ");";
  8. }
  9.  
  10. // ダミー：既にどこかで定義済みのはず
  11. int HANDLE_WM_MSG1(void* h, int l, int w, int function(void* hwnd, int,int) fn)
  12. {
  13.     return fn(h, l, w);
  14. }
  15. int HANDLE_WM_MSG2(void* h, int l, int w, int function(void* hwnd, int,int) fn)
  16. {
  17.     return fn(h, l, w);
  18. }
  19. int HANDLE_WM_MSG3(void* h, int l, int w, int function(void* hwnd, int,int) fn)
  20. {
  21.     return fn(h, l, w);
  22. }
  23.  
  24. // メッセージごとに作成する？
  25. const int WM_MSG1 = 1, WM_MSG2 = 2, WM_MSG3 = 3;
  26. int handler1(void* h, int l, int w) {
  27.     return 0;
  28. }
  29. int handler2(void* h, int l, int w) {
  30.     return 0;
  31. }
  32. int handler3(void* h, int l, int w) {
  33.     return 0;
  34. }
  35.  
  36. int main()
  37. {
  38.     int msg = WM_MSG1;
  39.     void* hwnd;
  40.     int wParam, lParam; // makeHANDLE_MSG を展開した後で参照される
  41.  
  42.     // 使用例
  43.     switch (msg) {
  44.         mixin( makeHANDLE_MSG!(hwnd, WM_MSG1, "handler1") ); // HANDLE_MSG(hwnd, message, fn)
  45.         // 複数行並べる場合はこっちのほうがマシ
  46.         mixin(
  47.             makeHANDLE_MSG!(hwnd, WM_MSG2, "handler2") ~
  48.             makeHANDLE_MSG!(hwnd, WM_MSG3, "handler3") ~
  49.             "" );
  50.         default:
  51.         assert(false);
  52.     }
  53. }
  54.  
Success #stdin #stdout 0.01s 1992KB
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https://ideone.com/oNThI
language:
D (dmd 2.085.0)
created:
11 years ago
visibility:
public

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