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1720 :: Help for code cleanup, avoid addr and cast

• Stefan_Salewski (orginal) [2015-10-18T00:19:31+02:00] view original

  For the Nim version of GTK 3.18 example application10 I have this code

  https://github.com/StefanSalewski/nim-gtk3/tree/master/test/application10

  I was able to avoid nealy all casts and addr operators, but in following code there are still two. Ideas to remove them?

  var app_entries = [
    gio.GActionEntryObj(name: "preferences", activate: preferences_activated, parameter_type: nil, state: nil, change_state: nil),
    gio.GActionEntryObj(name: "quit", activate: quit_activated, parameter_type: nil, state: nil, change_state: nil)]
  
  proc example_app_startup(app: gio.GApplication) {.cdecl.} =
    var
      builder: Builder
      app_menu: gio.GMenuModel
      quit_accels = [cstring "<Ctrl>Q", nil]
    g_application_class(example_app_parent_class).startup(app)
    add_action_entries(gio.g_action_map(app), addr app_entries[0], gint(len(app_entries)), app)
    set_accels_for_action(application(app), "app.quit",
                                        cast[cstringArray](addr quit_accels))
  Run

  For original C this was

  static GActionEntry app_entries[] =
  {
    { "preferences", preferences_activated, NULL, NULL, NULL },
    { "quit", quit_activated, NULL, NULL, NULL }
  };
  
  static void
  example_app_startup (GApplication *app)
  {
    GtkBuilder *builder;
    GMenuModel *app_menu;
    const gchar *quit_accels[2] = { "<Ctrl>Q", NULL };
    
    G_APPLICATION_CLASS (example_app_parent_class)->startup (app);
    
    g_action_map_add_action_entries (G_ACTION_MAP (app),
                                   app_entries, G_N_ELEMENTS (app_entries),
                                   app);
    gtk_application_set_accels_for_action (GTK_APPLICATION (app),
                                         "app.quit",
                                         quit_accels);

  And a related question:

  var text: cstring
  if text[0] == '\0': return
  Run

  Is there a more elegant way to test for empty cstring? I may prefer something like text[0] == "" if that works. Or may something like text.empty exist?

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• Araq (orginal) [2015-10-19T11:24:16+02:00] view original

  > Ideas to remove them?

  • system.allocCStringArray (But less efficient and you need to remember to dealloc it.)
  • Add an overloaded add_action_entries that takes an openArray and does the cast in the wrapper.

  And a related question

  system.nim doesn't really try to make cstring convenient to use.

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