From: Sean O'Dell <sean@...>
Date: 2004-06-17T03:09:10+09:00
Subject: Re: [BUG] Small bugs with frozen things

Just an idea regarding frozen objects: this and other myriad situations could 
be handled by object "states."  That is, when in a certain "state", only 
certain methods are available to an object, and those methods can be aliased.  
When state changes, the methods swap out.  For example, and this is just 
pseudocode, mind you (I am making up some syntax that doesn't really exist):

class MyClass

  def initialize
    state[:on] = false
  end

  def on_true
    return "TRUE"
  end

  def on_false
    return "FALSE"
  end

  alias :on :on_false

  state :on, :state => :on_state

end

m = MyClass.new
p m.on => "FALSE"
m.state[:on] = true
p m.on => "TRUE"

The way a frozen state could be implemented (aside from how it already is, 
this is just a from-scratch idea) would be through states.  Whenever an 
object state changes, it would first restore the last state it was in, so you 
could have a class like this:

class MyClass
  def initialize
    state[:frozen] = false
    @var = nil
  end

  def var
    @var
  end

  def var=(value)
    @var = value
  end

  state :frozen, :var= => nil
end

m = MyClass.new
p m.var => nil
m.var = "SOMEVALUE"
p m.var => "SOMEVALUE"
m.state[:frozen] = true
m.var = "ANOTHERVALUE" => no such method error

	Sean O'Dell