:mega: The proposal for unsigned integer types: <h...

# language-proposals

[ilya.gorbunov]

📣 The proposal for unsigned integer types: https://github.com/Kotlin/KEEP/issues/135

[karelpeeters]

Awesome, I've been looking forward to this! A question: how are the unsigned arrays implemented? How do they map to unsigned types? Also with inline classes?

[ilya.gorbunov]

Given that the compactness of storage is a requirement, unsigned arrays can also be inline classes wrapping the signed ones. Though there are other options in other platforms.

[Aregev2]

About the bitwise, why not implementing both shr and ushr?

[karelpeeters]

That's mentioned as one of the options.

[Aregev2]

Yeh I noticed, I think both will be the best option as it will create a confusion between their signed counterparts

[karelpeeters]

Both creates confusion too, what if both are used together in a project while there's no difference between them?

[Aregev2]

An inspection will be thrown, think it will cover that

[karelpeeters]

Might as well just pick one then.

[Aregev2]

Ok

[Aregev2]

Also, about the number literals, why not detecting if the number is out of the signed range, if so auto change it to it's unsigned form

[karelpeeters]

Number literals, right? fixed

[Aregev2]

Got me there @karelpeeters these are number literals 😁

[karelpeeters]

You're giving up some explicitness in order to have to type a single letter u less, I don't think that's worth it.

[elect]

it's really a pity they wont extend Number

[elect]

isn't possible to convert Number in an interface?

[Aregev2]

Maybe make an abstract class UnsignedNumber

[karelpeeters]

I don't really "get" the Number interface, there's not much you can do with them, right?

[elect]

what's the point to have it as an abstract class then?

[elect]

with an unique common base one could use Number for a generic number, unsigned included

[karelpeeters]

The interface is not the problem, it's the general idea: what can I do with a Number? There are some methods like .toDouble(), but those aren't useful because the result is not guaranteed to fit/be as accurate.

[rrader]

you can use it in generics bound

[karelpeeters]

Then what? I now have a value that implements Number, but I can't do anything with it.

[elect]

Exactly, I have for example in imgui a methods accepting a generic Number which can be either Int, Float, Double or Long. The original c++ version actually uses also unsigned. I won't be able to use the stlib unsigned because of this issue

[elect]

anyway, the point here is: can inline classes extend interfaces?

[Aregev2]

I think so..... How do I enable this feature tho?

[karelpeeters]

If you only allow some number types I think overloading is better. (until we have union types)

[karelpeeters]

@elect From https://github.com/Kotlin/KEEP/blob/unsigned_types/proposals/inline-classes.md:

Inline class can implement only interfaces

[elect]

that's a very good news, thanks