From: Jim Weirich <jweirich@...>
Date: 2003-08-03T07:46:20+09:00
Subject: Re: Home grown continuations

On Sat, 2003-08-02 at 12:02, Yukihiro Matsumoto wrote:

> Since 1.8, return within the closures created by proc or lambda, just
> terminates the closure execution.  

Huh?  I'm not sure I am understanding.  What should the following
return?

  def x
    10.times { |n| return 1 if n == 5 }
    2
  end
  p x

I would expect 1, but you seem to be saying 2.

> If you create a closure by
> Proc.new, it causes error, since call frame information is already
> lost unlike callcc.

So Proc.new is different?  What about the following code?

  def y
    p = Proc.new { |n| return 1 if n == 5 }
    10.times(&p)
    2
  end

Again, I would expect 1, but you seem to be saying it will be an error.

BTW, both return 1 in an not-very-recent version of 1.8.0.  (But that
might be different in the previews).

-- 
-- Jim Weirich       jweirich@one.net      http://onestepback.org
-----------------------------------------------------------------
"Beware of bugs in the above code; I have only proved it correct, 
not tried it." -- Donald Knuth (in a memo to Peter van Emde Boas)