From: Jos Backus <jos@...>
Date: 2004-12-02T16:26:58+09:00
Subject: Re: Accessing class constants from within a module?

On Thu, Dec 02, 2004 at 02:55:04PM +0900, Joel VanderWerf wrote:
> Jos Backus wrote:
> >Any idea how I can access a class constant from within a module when that
> >module is include'd in the class? I.o.w. how do I make this work?
> 
> Use dynamic lookup, rather than lexical lookup:
> 
> >module Debug
> >  def debug(level, msg)
> >    puts msg unless level > DEBUG # XXX DEBUG is wrong!
>       puts msg unless level > self.class::DEBUG
> >  end
> >end

It's things like these in Ruby that make my head spin :) But it does make
sense: at time of invocation we want to say either C1::DEBUG or C2::DEBUG,
depending on the invoking method. `::' can be preceded by any expression
yielding a class, in this case self.class. This evaluates to either C1 or C2,
as appropriate, and voila.

Thanks guys!

-- 
Jos Backus                       _/  _/_/_/      Sunnyvale, CA
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jos at catnook.com        _/_/   _/_/_/          require 'std/disclaimer'