[burntcookie90]

In what way? I've recently started writing in Swift and I find it to be less powerful than Kotlin. One such feature that's missing: extension expressions. Allows things like `let` and `with` from the kotlin stdlib

[Alphasite_]

What exactly are extension expressions, do you mean extension methods? If so, Swift does support them. I actually miss interface extensions in Kotlin, but thats a java cross compatibility issue.

[burntcookie90]

look at the signature for `with`

    inline fun <T, R> with(receiver: T, f: T.() -> R): R 

it takes a lambda that is scoped to the receiver type `T`. This means the lambda runs in the scope of whatever is passed in as a receiver.

    with(list) {
      add(item)
      add(item)
    }

This essentially lets you create DSLs for whatever.

Another thing that's bit me in butt recently is that `Protocol`s aren't concrete types, unlike an `interface` in Java/Kotlin.