From: ptkwt@...1.aracnet.com (Phil Tomson)
Date: 2003-01-22T04:57:59+09:00
Subject: accessors for module instance vars

I've got a module that that has several classes defined within it.  These 
classes need to access some instance variables defined at the module 
level.

For example:

module Evolvable
  PC = 0.2
  PM = 0.01
  def Evolvable.init(pc=Evolvable::PC,pm=Evolvable::PM,crossovertype=:uniform)
    @pc = pc
    @pm = pm
    @crossoverType = crossovertype
  end

  def Evolvable.get_pm
    @pm
  end

  def Evolvable.get_pc
    @pc
  end

  def Evolvable.get_crossoverType
    @crossoverType
  end
  #and set methods too

  class Population
    def initialize
      ...
    end

    def do_crossover(pc=Evolvable.get_pc, type=Evolvable.get_crossoverType)
      ...
    end

    def do_mutate(pm=Evolvable.get_pm)
      ...
    end
  end
end

#and to use it:

Evolvable.init(0.2, 0.01, :two_point)
#..later...
Evolvable.set_crossoverType :uniform
#do more stuff
#end

Now this works ok, but I'm wondering if there's a way to create the 
accessor methods for the Evolvable module automatically like with 
attr_accessor and attr_reader.  The problem with attr_accessor is that it 
creates an instance method, not a module method - is there a way to 
automatically create a module method?

Phil


-- 
"Or perhaps the truth is less interesting than the facts?" 
Amy Weiss (accusing theregister.co.uk of engaging in 'tabloid journalism')
Senior VP, Communications
Recording Industry Association of America