객체의 딥 클론

실현 1

class Object
  def dclone
    case self
    when Fixnum, Bignum, Float, NilClass, FalseClass, TrueClass, Continuation
      klone = self
    when Hash
      klone = self.clone
      self.each{|k, v| klone[k] = v.dclone}
    when Array
      klone = self.clone
      klone.clear
      self.each{|v| klone << v.dclone}
    else
      klone = self.clone
    end
    klone.instance_variables.each {|v|
      klone.instance_variable_set(v,
        klone.instance_variable_get(v).dclone)
    }
    klone
  end
end

 
실현

class Object
  def deep_clone
    _deep_clone({})
  end

  protected
  def _deep_clone(cloning_map)
    return cloning_map[self] if cloning_map.key? self
    cloning_obj = clone
    cloning_map[self] = cloning_obj
    cloning_obj.instance_variables.each do |var|
      val = cloning_obj.instance_variable_get(var)
      begin
        val = val._deep_clone(cloning_map)
      rescue TypeError
        next
      end
      cloning_obj.instance_variable_set(var, val)
    end
    cloning_obj
  end
end

class Array
  protected
  def _deep_clone(cloning_map)
    return cloning_map[self] if cloning_map.key? self
    cloning_obj = super
    cloning_obj.map! do |val|
      begin
        val = val._deep_clone(cloning_map)
      rescue TypeError
      end
      val
    end
    cloning_obj
  end
end

class Hash
  protected
  def _deep_clone(cloning_map)
    return cloning_map[self] if cloning_map.key? self
    cloning_obj = super
    pairs = cloning_obj.to_a
    cloning_obj.clear
    pairs.each do |pair|
      pair.map! do |val|
        begin
          val = val._deep_clone(cloning_map)
        rescue TypeError
        end
        val
      end
      cloning_obj[pair[0]] = pair[1]
    end
    cloning_obj
  end
end