From: Justin Collins <collinsj@...>
Date: 2006-10-28T05:38:58+09:00
Subject: Re: What are closures, continuations?

Joe Ruby MUDCRAP-CE wrote:
> I've seen these mentioned in various places. From what I can tell:
>
> - Ruby has closures -- which seem to be returning procs from functions?
> - Continuations may be planned for a future release of Ruby.
>
> If anybody can elaborate/correct, please feel free! Also, how would each 
> be useful?
>
> Thanks,
> Joe
>   

Closures are tricky, but you can think of them as blocks of code, or a 
way of making code a first-class object. Or as anonymous functions. Or 
as lambdas. There is a lot of documentation on them, I'd start with the 
Pickaxe book if you have it, or the online version if you do not.[1] 
Then google for "ruby blocks" and read what you can find to clarify. 
Also search this list for past discussions.

Continuations are currently available in Ruby[2], although, from what I 
understand, they are not widely used. There was a thread earlier about 
YARV (the "engine" for the next version of Ruby) not yet supporting 
continuations. That might be what you are thinking of.

-Justin

[1]http://ruby-doc.org/docs/ProgrammingRuby/html/tut_containers.html#UG
[2]http://ruby-doc.org/core/classes/Continuation.html