swift - Anonymous closure argument not contained in a closure

Question

Why doesn't this code work?

func function (param1 : Int, param2 : Int) -> Int {
    return $0 + $1
}

It produces an error:

Error: Anonymous closure argument not contained in a closure

Answer 1

It seems you can only access parameters by number inside anonymous closures, not functions.

For example:

var sevenMultiplyedByThree: Int = {
    return $0 * 3
}(7)

Also, this is just for anonymous parameters, so the following code will NOT work:

var sevenMultiplyedByThree: Int = {
    (namedParameter : Int) -> Int in
    return $0 * 3
}(7)