From: "David A. Black" <dblack@...>
Date: 2007-08-19T06:59:30+09:00
Subject: Re: method access to the enclosing method's locals?

Hi --

On Sun, 19 Aug 2007, david karapetyan wrote:

> Maybe you can answer another question. While trying to figure this out I
> kept running into scoping issues. The first thing that popped into my head
> was
>
> def go2(arg)
>  clos = proc {puts "Hi #{arg}"}
>  class << self
>    define_method(:hi,clos)
>  end
> end
>
> but this didn't work because for some reason when I'm inside the scope of
> class << self ... end define_method can't find clos even though it is inside
> the enclosing scope. Is there a reason classes don't close over their
> enclosing scope because I was thinking just like we can have closures we
> could also have closures for classes.

The class keyword always starts a new local scope, but class_eval
doesn't:

   x = 1
   Object.class_eval { puts x }    # 1

class/class_eval is analogous to def/define_method. class and def
start new local scopes; class_eval and define_method don't.


David

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