From: Bulat Ziganshin <bulatz@...>
Date: 2002-11-20T14:47:21+09:00
Subject: Re: ruby-dev summary 18711-18810

Hello Bob,

Tuesday, November 19, 2002, 8:59:03 PM, you wrote:

BA> that implements something like this. The implementation uses
BA> threads and queues, so is not very efficient. However, an API of
BA> this sort could possibly be implemented efficiently at a lower
BA> level. Here is the description from the top of the code:

ruby iterators insert iterator body in CALL STACK between caller code
and block evaluated by iterator - so that you hold a state of iterator
body but no state for iterated block

caller
 -> iterator
     -> block

".next-style" iterators use opposite scheme:

outside code
 -> loop body
    -> iterator body

if you want to hold BOTH state of iterator (local vars, ability to
do yield at different places) and state of loop (local vars, ability
to do .next at different places) you need coroutines

-- 
Best regards,
 Bulat                            mailto:bulatz@integ.ru