superclass(ancestor)のメソッドを再定義している時に、どの定義を使うか指定する

call_superclass_method.rb

$VERBOSE = true

class Super
  def a
    "super_a"
  end

  def b
    "super_b" + c
  end

  def c
    "super_c"
  end
end

class Sub < Super
  def a
    self.class.superclass.instance_method(:b).bind(self).call
  end

  def b
    "sub_b" + c
  end

  def c
    "sub_c"
  end
end

#=> "super_bsub_c"

modularized.rb

$VERBOSE = true

module MethodDefinedModuleAddressable
  def method(name, mod=nil)
    if mod
      mod.instance_method(name).bind self
    else
      super name
    end
  end
end

class Object
  include MethodDefinedModuleAddressable
end

class Super
  def a
    "super_a"
  end

  def b
    "super_b" + c
  end

  def c
    "super_c"
  end
end

class Sub < Super
  def a
    method(:b, Super).call
  end

  def a2
    method(:b).call
  end

  def b
    "sub_b" + c
  end

  def c
    "sub_c"
  end
end

p Sub.new.a #=> "super_bsub_c"
p Sub.new.a2 #=> "sub_bsub_c"