On Sat, Aug 08, 2020 at 01:47:27AM +0000, jmh530 via Digitalmars-d-learn wrote:
> On Friday, 7 August 2020 at 21:39:44 UTC, H. S. Teoh wrote:
> > [snip]
>
> "Furthermore, it can dispatch to a type-erased implementation ala Java
> -- at your choice;"
>
> This is interesting. Would you just cast to Object?
You could. Or you could introspect a type and dispatch a subset of types
to a type-erased implementation, say under some base class of your
choice or something. Or even something else altogether, like a C-style
void*-based implementation.
Or a hybrid, like this:
class ContainerBase {
class Node {
Node next, prev;
... // generic methods independent of element type
}
...
}
class Container(T) : ContainerBase {
class Node : ContainerBase.Node {
T payload;
... // T-specific methods
}
...
}
The code in ContainerBase deals with the element-independent part of the
container, essentially the type-erased component, whereas Container!T
retains type information for working with type-specific operations.
Result: reduced template bloat like Java generics, yet without giving up
the advantages of retaining element type information.
You couldn't do such a thing in Java, because Java-style generics simply
aren't powerful enough.
T
--
Truth, Sir, is a cow which will give [skeptics] no more milk, and so they are
gone to milk the bull. -- Sam. Johnson
