From: Ken Bloom <kbloom@...>
Date: 2008-04-19T00:10:06+09:00
Subject: Re: When are lambdas needed?

On Fri, 18 Apr 2008 05:43:49 -0500, David A. Black wrote:

> Hi --
> 
> On Fri, 18 Apr 2008, Ken Bloom wrote:
> 
>> The difference between lambda and the other ways of getting a Proc
>> object is that lambda treats return, next, and break a little bit
>> differently.
> 
> It's actually a difference between lambda and proc (which are synonyms),
> on the one hand, and Proc.new on the other:
> 
> irb(main):009:0> lambda { return }.call => nil
> irb(main):010:0> proc { return }.call => nil
> irb(main):011:0> Proc.new { return }.call LocalJumpError: unexpected
> return
> 
> Since it's a bit confusing to have proc and Proc.new be different, this
> has been changed in 1.9: proc and Proc.new are the same in 1.9, and
> lambda is different.
> 
> (I still have no idea how to memorize which is which.)

That's why I tried to be intentionally vague about the differences, but I 
guess I wasn't vague enough. Thanks everybody for filling in the details.

--Ken

-- 
Ken (Chanoch) Bloom. PhD candidate. Linguistic Cognition Laboratory.
Department of Computer Science. Illinois Institute of Technology.
http://www.iit.edu/~kbloom1/