On Friday, 21 August 2015 at 20:26:29 UTC, Walter Bright wrote:
On 8/21/2015 6:29 AM, Andrei Alexandrescu wrote:
Knee-jerk reaction: sensible and meaningful, but we need to
make a good case for
breaking code. -- Andrei
The case is:
https://issues.dlang.org/show_bug.cgi?id=14758
i.e. D being unusable for embedded systems because of bloat.
And it always has been a little strange to make every class
available via Object.factory. I have a hard time imagining an
application for it that needed more than a handful of classes
available that way.
The principle often used by languages (C, C++, Rust) is you
only pay for what you use. With Object.factory, every program
pays for it with every class, despite very few actual uses of
it.
That sound reasonable and I advocated for changing Object.factory
in the past for this very reason.
That being said, if we are going to break code, we'd better be
sure we do it for something that is worth it.
That mean we need a way for user to repro the feature, and I
rather avoid a dirty hack to do it, as proposed here. A generic
solution, for instance, could be for a superclass to be able to
mixin something in all its child.
Such a feature can be used to make sure that all child have a
mechanism to register themselves int he factory. Something à la
class Base {
super mixin {
shared this() {
library.register(typeid(typeof(this)));
}
}
}
class Child : Base {
// The super mixin also gets expanded here.
// But this does not have the same type.
// Both end up being registered, whatever that means.
}
Such a solution can be leveraged by any library or user to do
whatever they want. Sounds a better approach to me that
introducing hacks.
