On Wednesday, 14 November 2018 at 16:06:21 UTC, Chris Bare wrote:
If I have:
class base
{
void delegate(base) stored_dg;
void
add_function (void delegate (base) dlg)
{
stored_dg = dlg;
}
}
class A : base
{
this ()
{
super ();
add_function (&this.foo);
}
void foo (A a)
{
log ("i got here");
}
}
it fails because foo(A) does not match the parameter type of
delegate(base)
If I change foo (A a) to foo (base a)
It works, but this could be awkward in a deeper class hierarchy
where you
might not know the class name to use.
Is there a way to do this where foo's parameter type does not
to match the
class that implements add_function?
Thanks,
Chris
Are you looking for this?
https://dlang.org/phobos/std_traits.html#TransitiveBaseTypeTuple
It matches however not exactly your needs:
As all objects are derived from the Object class, you will always
get it as the common parent. So... with the trait, you get a list
but have still to make a decision which type to use.
