From: Mike Gold <mike.gold.4433@...>
Date: 2008-11-01T05:19:31+09:00
Subject: Re: How to access to local variables in enclosing scopes?

Yuh-Ruey Chen wrote:
> This is not what I'm really looking for. I don't care about accessing
> variables within another unrelated scope - in fact, unless explicitly
> allowed, it should not be allowed. I only care about accessing
> variables in enclosing scopes.

Just to verify we are on the same page: define_method solves all your 
problems, right?  If you don't wish to use Ruby 1.9 (which will be 
officially released in two months) then the corner case is default 
arguments, which can be done via the example I gave.

Keep in mind that you are looking at just one side of the coin.  There's 
a flip side to it.  Preventing local variables from willy-nilly 
infecting your methods is a Good Thing, and is usually what you want.

> x = 10
> 
> def foo
>   # how to access x from here?
> end
> 
> class Klass
>   # how to access x from here?
>   def bar
>     # how to access x from here?
>   end
> end

If you really want x to be globally accessible then you should do

require 'ostruct'
GLOBALS = OpenStruct.new
GLOBALS.x = 10

def foo
  GLOBALS.x
end

class Klass
  GLOBALS.x
  def bar
    GLOBALS.x
  end
end

This makes your intention explicit.  If you know python, you've probably 
heard the phrase, "Explicit is better than implicit."  :)
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