From: Ryan Pavlik <rpav@...>
Date: 2003-01-30T05:29:35+09:00
Subject: Re: Local variables & blocks

On Thu, 30 Jan 2003 01:46:54 +0900
ahoward <ahoward@fsl.noaa.gov> wrote:

<snip> Quote 1:
> so, correct me if i am wrong, but this does not address the need to do
> 
>   x = nil
>   a.each do |item|
>     x = ...
>   end
>   p x
> 
<snip> Quote 2:
> 
>   loop { export x; x = ... }
>   p x
> 
<snip> Quote 3:
>
>   x = nil
>   loop { x = ... }
>   p x
> 
<snip>

OK, this may seem an odd set of quotes, but I have a question.  What
happens when you do this:

   def munge(a)
      a.each {
         | i |
         export x;
         x = x + i
      }

      p x
   end

...and 'a' is empty?  'x' never happens.

Now, you say that Quote 2 would be exactly identical to Quote 3, but
it seems to me that it would be largely painful to search through
scopes to make sure you catch all initializations:

   def quux()
      proc {
         export x;

         proc {
            export y;

            proc {
               export z;
            }
         }
      }
   end

First of course is the question which scope each fall into (you said
"local" scope so I assume #quux-wide), and then you'd have to make
ruby hunt through all your blocks.  Then what happens if you pass one
as a parameter... where do exports go then? ;)

Plus, there's the most important consideration:

x = nil
export x
       ^--- One extra character to type!

;-)

-- 
Ryan Pavlik <rpav@users.sf.net>

"Ha! Who needs wits when you've got swords!" - 8BT