dfrib

// For details, see
// http://stackoverflow.com/questions/40261857/remove-nested-key-from-dictionary
import Foundation

extension Dictionary {       
    subscript(keyPath keyPath: String) -> Any? {
        get {
            guard let keyPath = Dictionary.keyPathKeys(forKeyPath: keyPath) 
                else { return nil }
            return getValue(forKeyPath: keyPath)

dfrib

// --------------------------------------------------------------- //
// Swift 3.0:                                                       
func fibs(through: Int, includingZero useZero: Bool = false)
    -> UnfoldSequence<Int, (Int, Int)> {
    return sequence(state: useZero ? (1, 0) : (0, 1),
                    next: { (pair: inout (Int, Int)) -> Int? in
        return pair.1 <= through ? {
            defer { pair = (pair.1, pair.0 + pair.1) }
            return pair.1 }() : nil
        })