require 'traits'
#
# the rememberance of traits can make generic intializers pretty slick 
#
class C 
  #
  # define class traits with defaults
  #
  class_traits(
    'a' => 40,
    'b' => 1,
    'c' => 0
  ) 

  #
  # define instance traits whose defaults come from readable class ones
  #
  class_rtraits.each{|ct| instance_trait ct => send(ct)}

  #
  # any option we respond_to? clobbers defaults
  #
  def initialize opts = {}
    opts.each{|k,v| send(k,v) if respond_to? k}
  end

  #
  # show anything we can read
  #
  def inspect
    self.class.rtraits.inject(0){|n,t| n += send(t)}
  end
end

c = C::new 'c' => 1
p c