submethods.rb

module Submethods
  def self.included(base)
    base.extend ClassMethods
  end

  module ClassMethods
    def submethods type = :public
      if self.class.name == "Object"
        return nil
      end
      parent = self.superclass
      methods = case type
      when :public, :pub, :pu
        self.public_methods - parent.public_methods
      when :private, :priv, :pri
        self.private_methods - parent.private_methods
      when :protected, :protect, :pro
        self.protected_methods - parent.protected_methods
      when :inst_public, :inst_pub, :inst_pu, :public_inst, :pub_inst, :pu_inst
        self.public_instance_methods - parent.public_instance_methods
      when :inst_private, :inst_priv, :inst_pri, :private_inst, :priv_inst, :pri_inst
        self.private_instance_methods - parent.private_instance_methods
      when :inst_protected, :inst_protect, :inst_pro, :protected_inst, :protect_inst, :pro_inst
        self.protected_instance_methods - parent.protected_instance_methods
      else
        raise "Unknown method type #{type.to_s}"
      end
      puts methods.sort.join("\n")
      nil
    end
  end
end

class Object
  include Submethods
end