From: Charles Steinman <acharlieblue@...>
Date: 2005-07-29T04:06:01+09:00
Subject: Re: Method Scopes


Trans wrote:
> I would like to see Ruby gain a "scoping feature" (I usually refer to
> this as a "namespace", but looking at Matz' discussion of Rite he's
> using that to mean something else). This idea is this:
>
>   class String
>
>     scope format
>
>       def jumble
>         j = ''
>         split(//).each_with_index{ |c,i| j << ( i % 2 == 0 ? c.downcase
> : c.upcase ) }
>         j
>       end
>
>     end
>
>   end
>
>   "Wizard".format.jumble  #=> wIzArD
>
>
> Currently I can implement like so:
>
>   require 'delegate'
>
>   class String
>
>     def format
>       @__format__ ||= Format.new( self )
>     end
>
>     class Format < DelegateClass( self )
>
>       def jumble
>         j = ''
>         split(//).each_with_index{ |c,i| j << ( i % 2 == 0 ? c.downcase
> : c.upcase ) }
>         j
>       end
>
>     end
>
>   end
>
> But that has a whole lot of icky overhead. I would be nice if Ruby
> could support this kind of thing natively. It's a nice way to organize
> methods.

I wouldn't be hard to create a Class#scope method that could do syntax
very much like your first example. Just have it create a delegate class
and instance_eval a passed block so it's executed in the scope of that
class.