Swift recursive flatmap (Alternative version)

gistfile1.swift

protocol AnyArray{}/*<--Neat trick to assert if a value is an Array, use-full in reflection and when the value is Any but really an array*/
extension Array:AnyArray{}//Maybe rename to ArrayType
func recFlatMap<T>(_ arr:[AnyObject]) -> [T]{
    var result:[T] = []
    Swift.print("arr.count: " + "\(arr.count)")
    arr.forEach{
        if($0 is AnyArray){
            let a:[AnyObject] = $0 as! [AnyObject]
            result += recFlatMap(a)
        }else{
            result.append($0 as! T)
        }
    }
    return result
}