> On Aug 19, 2024, at 7:37 PM, Rob Landers <rob@bottled.codes> wrote:
> As an experiment, awhile ago, I went a different route for reified generics
> by 'hacking' type aliases (which I was also experimenting with). Such that a
> generic becomes compiled into a concrete implementation with a dangling type
> alias:
>
> class Box<T> {
> function __construct(T $thing) {}
> }
>
> is essentially compiled to
>
> class Box {
> use alias __Box_T => ???;
>
> function __construct(__Box_T $thing) {}
> }
>
> This just gets a T type alias (empty-ish, with a mangled name) that gets
> filled in during runtime (every instance gets its own type alias table, and
> uses that along with the file alias table). There shouldn't be any
> performance impact this way (or at least, as bad as using type aliases, in
> general; which is also an oft-requested feature).
From what I understand this is essentially how Go implements Generics. So +1
for considering this approach.
> FYI though, people seemed really turned off by file-level type aliases (at
> least exposed to user-land, so I never actually pursued it).
Shame. Type aliases are super useful in practice in other languages, with many
used for single-file scope in my experience.
-Mike
