On Thursday, 16 January 2014 at 18:50:26 UTC, Vladimir Panteleev
wrote:
On Thursday, 16 January 2014 at 09:28:18 UTC, Boyd wrote:
For extending, there is the 'protected' attribute, but it's
specific for class overriding only. Very often, extensions are
not merely limited to derived classes. What I find myself
wanting is more like the 'package' attribute, except it needs
to work outside of the package as well.
You can make class members accessible to a module by
reintroducing them in a derived class using an alias. It even
works for static and final methods, and field variables.
Example:
///////////////////////////////////////////////////////////
module library;
class Button
{
protected void click() {}
}
///////////////////////////////////////////////////////////
module user;
import library;
void main()
{
auto button = new Button();
button.click(); // NG
}
///////////////////////////////////////////////////////////
module extender;
import library;
class ExtendedButton : Button
{
// reintroduce protected member as private to this scope
private alias Button.click click;
}
void main()
{
auto button = new ExtendedButton();
button.click(); // OK
}
///////////////////////////////////////////////////////////
HTH.
While it would work in this case, extending the class is not
always an option. Plus it seems quite a big and dirty-looking
work around for something that should, in my opinion, be quite
simple.
