in src/main/scala/kotlin/KotlinVersion.scala [66:75]
private def parseKind(kindSuffix: String, prefix: String)(constructor: Option[Int] => Kind): Option[Kind] = {
assert(kindSuffix.startsWith(prefix), s"""Prefix "$prefix" not found in kind suffix "$kindSuffix"""")
val numberString = kindSuffix.drop(prefix.length).stripSuffix("-release")
if (numberString.isEmpty) Some(constructor(None))
else {
val number = numberString.toIntOption
Option.when(number.isDefined)(constructor(number))
}
}