Could some contract be added to `Int.sign` to supp...

# stdlib

[arekolek]

Could some contract be added to Int.sign to support this?

val foo = when (a.compareTo(b).sign) {
    -1 -> SomeEnum.LEFT
    0 -> SomeEnum.NONE
    1 -> SomeEnum.RIGHT
}

Does the contract API support something like this?

[karelpeeters]

I don't think the current contract system supports this, maybe suggest it on the KEEP tracking issue?

A related language feature I'd like is to make when smarter and have it consider this to be exhaustive:

val x: Int
val s = when {
    x < 0 -> -1
    x == 0 -> 0
    x > 0 -> 1
}

[miha-x64]

This can be solved without special compiler features by returning enum from sign

[arekolek]

Int.sign is in stdlib, that’s why I posted in #stdlib

[arekolek]

I don’t expect they are going to change its return type

[karelpeeters]

Thinking about it more this really would be an anti-feature, you're supposed to use an enum instead. Of course it's too late for that in this case.

[arekolek]

But sometimes you need sign to return an Int, for example it can appear in some math formulas

[karelpeeters]

x.sign.toInt() simple smile

[karelpeeters]

But yeah the current choice makes sense as well.