[core] Add numeric.PosInt

[kevin-lee]

Summary

[core] Add numeric.PosInt

Version

unreleased

Description

PosInt(1) // compiles
PosInt(0) // compile-time error
PosInt(-1) // compile-time error

PosInt.from(123)
// Either[String, PosInt] = Right(PosInt(123))

PosInt.from(-123)
// Either[String, PosInt] = Left(Invalid value: -123. It must be a positive Int)

PosInt.unsafeFrom(999)
// PosInt = PosInt(999)

PosInt.unsafeFrom(-999)
// IllegalArgumentException(Invalid value: -999. It must be a positive Int) is thrown