I started to use unsigned integers and I was surpr...

# stdlib

[Norbi]

I started to use unsigned integers and I was surprised that I cannot use them where a Number is expected (in my case it was a generic function with a type parameter <T: Number>).
I have checked the corresponding KEEP and found this:

Number is an abstract class in Kotlin, and inline classes are not allowed to extend other classes, therefore unsigned types can't be inherited from Number class.

We haven't found compelling use cases to circumvent this limitation specially for the unsigned types.

My questions:
1. Is it really "good enough" to have non-unified "number" handling in Kotlin?
2. Why is Number an abstract class and not an interface? It has only some abstract functions, nothing else.
Thanks.

[ephemient]

1. you can't do arithmetic on Number anyway, it's almost never useful, so IMO it's fine.
2. that's how it is in Java, and Kotlin can't change the shape of the existing class hierarchy

[Norbi]

you can't do arithmetic on Number anyway, it's almost never useful, so IMO it's fine

It's true, the function I mentioned calls only toInt() on the <T: Number>.
Not a big deal, I create an overloaded variant of the function, I was just curious.

that's how it is in Java

I knew it that it was because of Java compatibility! 🙂

Thanks.

[elect]

I disagree, doing arithmetic on Number is useful when you have to perform the same operations on generic number inputs (eg: slider in UI). Right now I'm forced to duplicate some code because of that.
That's exactly the biggest reason I'm locked on keep using unsigned