From: "James F.Hranicky" <jfh@...>
Date: 2002-09-13T00:21:17+09:00
Subject: Re: private variables

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On Thu, 12 Sep 2002 23:17:03 +0900
Dave Thomas <Dave@PragmaticProgrammer.com> wrote:

> "Christoph" <chr_news@gmx.net> writes:
> 
> > which means one more set of scoping rules to keep mind?  (Probably
> > not, but even the prospect makes me shudder;-)
> 
> Actually, that raises an interesting point.
> 
> If we're (somewhat unfortunately, imo) using '_' to denote 'localized',
> then should we be using more orthogonally?
> 
>   @_a  - localized instance variable
> 
> 
>   _a   - localized block variable,
> 
>        _a = 1
> 
>        10.times {|_a| puts _a}
> 
>        puts _a  # => 1
> 
> 
> If we're going down this route (and I'm wondering if I think we
> should), then we can at least make us of the options.

How about an attr_private directive?

  class Foo
      attr_accessor :a, :b;
      attr_private  :c
  end

  class Bar < Foo
      attr_accessor :c
  end

  x = Bar.new
  p x.c	# Actually using Bar::c, not Foo::c

Seems syntactically cleaner to me. Of course, throwing back to the local block 
variable thing, how about

  - default to all local, indicate lookups in previous scopes with :: 

	foo.each { |x,::y| 

		a = x 		# local a modified, value of local x
		::b = y		# global b now value of global y

	}
?

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