Is there a plan to do something about the platform type marker `!`? 'Cause <Java is introducing> `T!...

# language-evolution

[Loney Chou]

Is there a plan to do something about the platform type marker !? 'Cause Java is introducing T! as non-null type marker and it could be a bit confusing from Kotlin's perspective in the future.

[CLOVIS]

I wonder. It's an important part of the language, so changing it is difficult.

But also, it can't appear in code, so maybe it's a purely cosmetic change? I mean, using another symbol shouldn't break existing code, right?

[Ben Woodworth]

Petition to move to the interrobang for platform types 👀

Mostly joking, though it could be a pretty intuitive analogy for communicating unknown nullable/non-null (`?/!`) types

[CLOVIS]

I mean… If we can't type it anyway, does it matter that it's unicode?

[CLOVIS]

I do like the idea, String‽ has a nice look

[CLOVIS]

the Slack font makes it a bit hard to read though

[ephemient]

there's so many possibilities with unicode ;)

String⁉
String⁈
String‼
⸮String
¿String
¡String
⸘String

[mikhail.zarechenskiy]

No plans so far, the proposal is still in its early stages, and as you mentioned, our T! notation is used only internally. For instance, in the IDE, we could treat String! as regular non-null String types in Kotlin, but load String from Java as String..String? to avoid confusion

[Klitos Kyriacou]

I hope not! I wouldn't like to see a platform type referred to as ConcurrentNavigableMap<AsynchronousByteChannel..AsynchronousByteChannel?, RandomAccessFile..RandomAccessFile?>..ConcurrentNavigableMap?<AsynchronousByteChannel..AsynchronousByteChannel?, RandomAccessFile..RandomAccessFile?>

[Loney Chou]

How about ConcurrentNavigableMap<AsynchronousByteChannel(?), RandomAccessFile(?)>(?)? Just mark it as "optional"?

[Loney Chou]

Also another similar thing I'd like to propose: When using Java builtin collection types, show them as (Mutable)X, such as (Mutable)List. Currently the MutableList..List thing is a little obscuring. So combined with (?), it now shows (Mutable)List<String(?)>(?) (try to imagine the .. form).

[Klitos Kyriacou]

But the ClassName(?) syntax would look a little bit like a constructor call.

[Michael de Kaste]

Maybe just 😬

ConcurrentNavigableMap<AsynchronousByteChannel!?, RandomAccesFile!?>!?

[Nanami]

why is the code screaming at me!?

[Michael de Kaste]

because it's Java (interop), thats cause for screaming 😬