From: Stefano Zacchiroli <zack@...>
Date: 2007-01-22T02:32:11+09:00
Subject: module global variables

Is there a way to define per-module global variables? My best
approximation is the following

  module Foo
    @@x = 0
    def do_something_on_x
      @@x = ...
    end
    def x
      @@x
    end
  end

The drawbacks are that I haven't found anything similar to
attr_reader/writer/... for instance variables.

If interested in the real use case here it is: I've defined a module
which include a set of common functionalities which need to deliver
messages with a given verbosity. I want to avoid to pass the verbosity
configuration to all the involved class and methods but I want to avoid
to use a global $verbosity variable since the setting should be limited
to all the functionalities implemented by my module.

Here is how I'm using the verbosity setting:

  module Foo
    @@verbosity = 0
    def incr_verbosity
      @@verbosity += 1
    end
    def verbosity
      @@verbosity
    end
  end

I would love to write something like

  module Foo
    @@verbosity = 0
    module_attr_reader :verbosity
    def incr_verbosity
      @@verbosity += 1
    end
  end

Am I using the wrong tool for my end?

Many thanks in advance,
Cheers.

-- 
Stefano Zacchiroli -*- Computer Science PhD student @ Uny Bologna, Italy
zack@{cs.unibo.it,debian.org,bononia.it} -%- http://www.bononia.it/zack/
(15:56:48)  Zack: e la demo dema ?    /\    All one has to do is hit the
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