Enchancements for when statement

Language Design
1 
when (test(_) == MyThing.ONE) {
   "hello" -> { /* ... */ }
   "hi" -> { /* ... */ }
   "greetings" -> { /* ... */ }
   "yo" -> { /* ... */ }
}

Now for each entry, it would be evaluated with the argument from _.
If you broke it down to another when statement, it would look like this.

when (MyThing.ONE) {
   test("hello") -> { /* ... */ }
   test("hi") -> { /* ... */ }
   test("greetings") -> { /* ... */ }
   test("yo") -> { /* ... */ }
}

This feature could perhaps go into multiple when arguments too.

when (test(_).func(_) == MyThing.ONE) {
   "hello", 30 -> { /* ... */ }
   "hi", 20 -> { /* ... */ }
   "greetings", 50 -> { /* ... */ }
   "yo", 10 -> { /* ... */ }
}
2

There’s a discussion about adding pattern matching here that you might be interested in:

There’s also a new #pattern-matching channel on the Kotlin Slack