From: "David A. Black" <dblack@...>
Date: 2008-04-18T19:43:49+09:00
Subject: Re: When are lambdas needed?

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.)


David

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