定数の参照 - 前にruby-listへ投稿したけど特に反応が得られなかったもの http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/48791

lookup_const.rb

$VERBOSE = true

class Super
  class << self
    CONS = :Singleton
  end

  CONS = :Super
end

class Sub < Super
  CONS = :Sub
end

class Sub
  class << self
                         # 1
    p CONS               #=> :Sub
    p const_get(:CONS)   #=> :Singleton
  end
end

class << Sub
                         # 2
  p CONS                 #=> :Singleton
  p const_get(:CONS)     #=> :Singleton
end

class Sub
  class Nested < Super
                         # 3
    p CONS               #=> :Sub
    p const_get(:CONS)   #=> :Super
  end
end

class Sub::Nested
                         # 4
  p CONS                 #=> :Super
  p const_get(:CONS)     #=> :Super
end