From: Suraj Kurapati <snk@...>
Date: 2008-06-24T00:10:28+09:00
Subject: Re: Is it ellegant to use a global variable to store a Logger   object?

Robert Klemme wrote:
> On 23.06.2008 03:29, Suraj Kurapati wrote:
>> I�aki Baz Castillo wrote:
>>> Humm, I don't like adding "include Logging" to every classes I use since
>>> sometimes I use objects, sometimes classes, so I'd also need to "extend" 
>>> some classes not just "include".
>> 
>> You could use meta programming to include Logging in all nested classes 
>> and modules of your top-level module:
> 
> Now things are becoming quite complex.

Not really.  You can refactor that bit of meta programming into its own 
module:

  module AddLoggingToNested
    def self.included target
      # ... code from previous e-mail ...

      extender[target]
    end
  end

Now, you can add this propagation of logging functionality to any 
top-level module or class by simply doing:

  module MyProjectTopLevel
    # ...

    include AddLoggingToNested
  end

Note that the include musts be done *after* all nested classes have been 
defined.  That is why I put that include() statement at the bottom of 
the module's code.
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