On 7/14/15 11:28 AM, Rene Zwanenburg wrote:
Given the following code:
class Base
{
alias CallbackType = void delegate(Base);
CallbackType callback;
void foo()
{
callback(this);
}
}
class Derived : Base
{
}
void main()
{
auto d = new Derived();
d.callback = (Derived d) { /* Do something */ }
}
Obviously this won't compile, since the callback function needs to have
Base as parameter, not Derived. But the given code is perfectly safe
because in main d typed as Derived, not Base. Does anyone know a clean
way to support the code given in main(), preferably by defining some
smart CallbackType so Derived doesn't need to be modified?
No, this isn't possible. Only thing you can do is:
d.callback = (Base b) { if(auto d = cast(Derived)b) { /* Do something */
} else assert(0); };
-Steve
