From: "Hal E. Fulton" <hal9000@...>
Date: 2003-05-09T08:23:52+09:00
Subject: Re: Can a global be a constant?

----- Original Message ----- 
From: "Jim Freeze" <jim@freeze.org>
To: "ruby-talk ML" <ruby-talk@ruby-lang.org>
Sent: Thursday, May 08, 2003 6:02 PM
Subject: Re: Can a global be a constant?


> > I've also noticed that we don't mind that a class is
> > global, if you know what I mean. You could always
> > encapsulate all your global data in a class called
> > State (with class variables and accessors for them).
> > 
> > Then you could pretend to be doing something clever
> > when actually you're just using one big fancy global
> > variable. :)
> 
> Ok, <stupid question> so how would you
> access the state object in the code below without
> making it a global as I did?  </stupid question>
> 
> class App
>   State = ::Struct.new(:debug, :verbose)
>   $state = State.new(true, false)
>   def main
>     Work.new
>   end
> end
> 
> class Work
>   def initialize
>     puts $state.debug
>   end
> end
> 
> App.new.main

Not a stupid question... maybe my assumptions
don't work for you, but what I was thinking 
was something like:

class State
  @@debug = nil
  @@verbose = nil

  def State.debug
    @@debug
  end

  def State.debug=(val)
    @@debug = val
  end

  def State.verbose
    @@verbose
  end

  def State.verbose=(val)
    @@verbose = val
  end

class App
  def main
    State.debug = true
    State.verbose = false
    Work.new
  end
end

class Work
  def initialize
    puts State.debug
  end
end

App.new.main


Hal