From: Christopher Armstrong <radix@...>
Date: 2003-07-27T10:53:42+09:00
Subject: Throwing exceptions into continuations.

Hi all. I'm playing around with Ruby because I like experimenting with
concurrency systems, and found out it has continuations.

I'm going to be calling user-defined code inside of a callcc block,
and the user-defined code will either return a value or raise an
error, and I want that value or error to be passed on to the
continuation.

I can't find any way to throw into the continuation. If there is no
way, can I request that a #throw method be added, or something like
that?

The only alternative I could think of is to have special code on the
calling side of the callcc that will watch the return value to see if
it is a array of two elements, the first being
:special-internal-throw-exception-bit, and if so, throwing the second
element of the array. This isn't what I want, though, especially
because it won't maintain the stack trace from the other side.

-- 
 Twisted | Christopher Armstrong: International Man of Twistery
  Radix  |          Release Manager,  Twisted Project
---------+     http://twistedmatrix.com/users/radix.twistd/