#
# default values may be given either directly or as a block which will be
# evaluated in the context of self.  in both cases (value or block) the
# default is set only once and only if needed - it's a lazy evaluation.
#
  require 'attributes'

  class C
    attribute :a => 42
    attribute(:b){ Float a }
  end

  c = C.new

  p c.a
  p c.b