Thread-safe memoization

Question

Let\'s take Wes Dyer\'s approach to function memoization as the starting point:

public static Func Memoize(this Func f)
{         


        

Answer 1

If you already have that Lazy type, I assume you're using .net 4.0, so you could also use the ConcurrentDictionary:

public static Func Memoize(this Func f)
{
  var map = new ConcurrentDictionary>();
  return a =>
    {
      Lazy lazy = new Lazy(() => f(a), LazyExecutionMode.EnsureSingleThreadSafeExecution);
      if(!map.TryAdd(a, lazy))
      {
        return map[a].Value;
      }
      return lazy.Value;
    };
}