On Wednesday, 5 September 2018 at 18:41:15 UTC, Jacob Carlborg
wrote:
On 2018-09-04 06:03, Mike Franklin wrote:
For that it needs to support all the features as classes do
today. In that case, what would be the difference compared to
classes?
Indeed, the idea is that structs, with a few additional features
added to the language, should be able to fill the role classes
fill today.
Polymorphism can be achieved in the library using methods similar
to what Sarn demonstrated in the article I linked previously.
Features like mixins can cut down on the boilerplate; other
boilerplate-removing features would likely be needed.
Multiple-alias-this and some form of `protected` for structs
would be examples of additional features that would help to
implement class-like behavior; again, others would also likely be
needed.
Reference semantics can be achieved much like C++ does today with
it's smart pointers and things like `T&`. For example, D might
have `GC<T>` for garbage-collected types, `RC<T>` for reference
counted types, etc, so the ownership and reference semantics are
delegated to a container type in concert with DIP1000-like
features of some kind.
In general, classes, to me, are looking more and more like syntax
sugar over existing fundamental language features, and I think
with the right supplemental language features for reducing
boilerplate and encapsulate details, something very much like
classes can be implemented in the library. I'm just thinking
out-loud though. I doubt something like this will happen,
especially without me or someone else demonstrating such a thing
with a thorough proof-of-concept implementation.
Mike
