Memoize 1-parameter function.

gistfile1.scala

def memoize[T, U](f: T => U) = {
    val cache = scala.collection.mutable.HashMap[T, U]()
    (t: T) => {
        if (!cache.contains(t)) {
            cache.put(t, f(t))
        }
        cache.get(t).get
    }
}

val fib: (Int => BigInt) = memoize {
    n => if (n < 2) n else fib(n - 1) + fib(n - 2)
}