Why isn't the `Number` interface extending `Compa...

# language-proposals

[holgerbrandl]

Why isn't the Number interface extending Comparable ? Being a number always superimposes an ordering imho.

[louiscad]

Because of NaN?

[holgerbrandl]

I see the argument, but in fact Double is implemented as Double private constructor() : Number(), Comparable<Double> in the standard library, which somehow argues against it. AFAIK all other subtypes of Number (excluding Double and Flot) don't have a NaN value

[louiscad]

You're right. I guess it's because Java's Number doesn't either? Regardless, it's pretty easy to make your own comparator that does a conversion beforehand.

[Fleshgrinder]

The number interface is generally useless.

[Ruckus]

I would guess because because numbers aren't meant to be comparable against all other number types (that is, `Int`s should only be compared to `Int`s, not to `Number`s) and they didn't want some sort of Number<T: Number<T>>.

[Ruckus]

As to why, I would guess because most of the numbers are primitives, so generic constraints don't really work at the byte code level, but I could be wrong.

[Ben Woodworth]

Also keep in mind that not all sets of numbers are ordered, such as complex numbers

[Ruckus]

True, though I think that's a bit too theoretical for this since complex numbers don't really fit the Number interface anyway.