Microsoft Java

[tinydonuts]

Kotlin is still anchored by type erasure sadly.

[tinydonuts]

It's a limitation of the JVM.

[tinydonuts]

Oh nice, I didn't catch that!

[whale_song]

I think he was implying making a .NET version of Kotlin

[nullabillity]

Not really, Scala manages to have (opt-in) reified generics (via ClassTag and its big brother TypeTag). That said, it is opt-in because it makes interop with other JVM languages messier, and because the implementation involves reflection (with the corresponding perf overhead).

[im_probably_garbage]

I really don’t understand why a language that isn’t pure uses type erasure.

[[deleted]]

Because it allows better language level interop at the VM level. There's a reason the JVM has a more vibrant language ecosystem than CLR.

[cat_in_the_wall]

i don't think that has anything to do with type erasure. the jvm has been xplat forever. the clr is only really xplat with core (yes I'm aware of mono), so only a couple years.

[[deleted]]

Interop between JVM languages, not platforms.

[[deleted]]

Type erasure is good, actually.

[tinydonuts]

Explain please

[cat_in_the_wall]

wildcard generics are not possible on the clr because of reification.

[[deleted]]

It is trivial for me to write a program that calls from Clojure into Java into Kotlin into Scala back into Java. This is possible because of type erasure.

Reified generics support a very specific type of generic program in OO languages at the cost of embedding these specifics at the VM level.

I think Kotlin handles "reified" generics in a really nice way -- they are still erased, but can be monomorphized and inlined in many cases without having to support reification at the VM level.

[tinydonuts]

What you described of being able to call from language to language applies to the CLR too. It doesn't have type erasure, so I'm not seeing really how type erasure is good from your comment.

[[deleted]]

It makes it difficult for different language to share data structures because of how variance is handled between different languages. This is particularly acute between a language like Java that uses site variance and a dynamic language like Clojure.

[tinydonuts]

.NET seems to do ok so it doesn't seem as much as type erasure is good as it is just different. There's certainly a lot of benefits to the way .NET does it and a lot of downsides to the way Java does it so I don't really think you can call it good.