From: Gregory Brown <gregory.t.brown@...>
Date: 2007-07-04T22:52:26+09:00
Subject: Re: block params scoping (was ruby-talk 257917: RE: Using a block to surround a string?)

On 7/4/07, Pe�a, Botp <botp@delmonte-phil.com> wrote:
> Fr David Black:
> # Method definitions always have their own local scope, so a, b, and
> # string are strictly local to the method.  Blocks pick up the scope
> # that they're created in, and can also create variables that weren't
> # already in that scope.  Those variables disappear when the block
> # exits; the ones that were there already survive:
> #
> #    x = 1
> #    some_method { y = x + 1 }   # same x; new y
> #    y                           # undefined; block's y didn't survive
> #    x                           # same x
>
> Hi David,
>
> How about parameter variables, will its scoping change/stay in ruby2 ?
>
> Currently,
>
> irb(main):011:0> x="testing"
> => "testing"
> irb(main):012:0> 5.times{|x|}
> => 5
> irb(main):013:0> x
> => 4
>
> i'd prefer
>
> x = "testing"
> some_method { |x| y = x + 1 }   # different x; overrides any x
> x                               # => "testing", same x outside
>

Hi, example from Eigenclass[0]:

a = 1
10.times{|a| } # !> shadowing outer local variable - a
a  # => 1

looks like it throws a warning and behaves as we all want it to. :)

Man, this list of changes is fun. :)

-greg

[0] http://eigenclass.org/hiki.rb?Changes+in+Ruby+1.9#l41