class UserDefined

  class Nested
    def ==(other)
      other.kind_of? self.class
    end
  end

  attr_reader :a, :b

  def initialize
    @a = 'stuff'
    @b = @a
  end

  def _dump(depth)
    Marshal.dump [@a, @b]
  end

  def self._load(data)
    a, b = Marshal.load data

    obj = allocate
    obj.instance_variable_set :@a, a
    obj.instance_variable_set :@b, b

    obj
  end

  def ==(other)
    self.class === other and
    @a == other.a and
    @b == other.b
  end

end

class UserDefinedWithIvar
  attr_reader :a, :b, :c

  def initialize
    @a = 'stuff'
    @a.instance_variable_set :@foo, :UserDefinedWithIvar
    @b = 'more'
    @c = @b
  end

  def _dump(depth)
    Marshal.dump [@a, @b, @c]
  end

  def self._load(data)
    a, b, c = Marshal.load data

    obj = allocate
    obj.instance_variable_set :@a, a
    obj.instance_variable_set :@b, b
    obj.instance_variable_set :@c, c

    obj
  end

  def ==(other)
    self.class === other and
    @a == other.a and
    @b == other.b and
    @c == other.c and
    @a.instance_variable_get(:@foo) == other.a.instance_variable_get(:@foo)
  end
end
 
arr = []
myproc = Proc.new { |o| arr << o }
o1 = UserDefined.new; 
o2 = UserDefinedWithIvar.new
obj = [o1, o2, o1, o2]
Marshal.load Marshal.dump(obj), myproc
p arr == [o1, o2, obj]