memoize.swift

func memoize<A: Hashable, R>(block:(A, (A->R))->R)->(A->R) {
    var memo:Dictionary<A,R> = [:]
    var result:(A->R)!
    result = {
        if let l = memo[$0] { return l }
        let r = block($0, result)
        memo[$0] = r
        return r
    }
    return result
}

// let fib = memoize { n, f in n <= 1 ? 1 : f(n-2)+f(n-1) }
let fib = memoize { $0 <= 1 ? 1 : $1($0-2)+$1($0-1) }
for i in 0...63 { print(fib(i)) }