enumerators

I was wondering if there is any concurrency (now or future), or performance benefit to using yield return over returning a list. See the following examples Processing Method void Page_Load() { foreach(var item in GetPostedItems()) Process(item); } using yield return IEnumerable<string> GetPostedItems() { yield return Item1.Text; yield return Item2.Text; yield return Item3.Text; } returning a list IEnumerable<string> GetPostedItems() { var list = new List<string>(); list.Add(Item1.Text); list.Add(Item2.Text); list.Add(Item3.Text); return list; } In the yield return example, the result is

This question is not about how to use Enumerators in Ruby 1.9.1 but rather I am curious how they work. Here is some code: class Bunk def initialize @h = [*1..100] end def each if !block_given? enum_for(:each) else 0.upto(@h.length) { |i| yield @h[i] } end end end In the above code I can use e = Bunk.new.each , and then e.next , e.next to get each successive element, but how exactly is it suspending execution and then resuming at the right spot? I am aware that if the yield in the 0.upto is replaced with Fiber.yield then it's easy to understand, but that is not the case here. It is a plain old

I'd like to hear from someone with a deeper understanding than myself what the fundamental differences are between Enumerators , Conduits , and Pipes as well as the key benefits and drawbacks. Some discussion's already ongoing but it'd be nice to have a high-level overview. Philip JF Enumerators/Iteratees as an abstraction were invented by Oleg Kiselyov. They provide a clean way of doing IO with predictable (low) resource requirements. The current Enumerators package is pretty close to Oleg's original work. Conduits were created for the Yesod web framework. My understanding is that they were