[Ruby] dup_if - dupできるオブジェクトは複製し、そうでなければselfを返すメソッド

dup_if.rb

class Object
  def dup_if
    begin
      self.dup
    rescue TypeError
      self
    end
  end
  
  def clone_if
    begin
      self.clone
    rescue TypeError
      self
    end
  end
  
  def duplicable?
    begin
      self.dup
    rescue TypeError
      return false
    end
    true
  end
  
  def clonable?
    begin
      self.clone
    rescue TypeError
      return false
    end
    true
  end
end

# 実行例
if $0 == __FILE__
  x = "hoge"
  y = x.dup_if
  puts x.object_id == y.object_id # expected false
  
  x = 42
  y = x.dup_if
  puts x.object_id == y.object_id # expected true
end