Memoization in Bike

memoize.bk

func memoize(f) {
  var cache = {
    member_missing: func() { null }
  };
  return func recur(n) {
    cache[n] || (cache[n] = f(recur, n));
  };
}

var fib = func(n) {
  n < 2 ? 1 : fib(n-1) + fib(n-2)
};

var m_fib = memoize(func(recur, n) {
  n < 2 ? 1 : recur(n-1) + recur(n-2);
});

load 'stopwatch.bk';
var watch = Bike.Stopwatch.create( ).start( );
println('fib(20) = {0} (elapsed: {1}ms)', fib(20), watch.stop());

watch.reset().start();
println('m_fib(20) = {0} (elapsed: {1}ms)', m_fib(20), watch.stop());