From: "Damián M. González" <lists@...>
Date: 2013-03-07T02:35:30+09:00
Subject: Re: Persisting and loading objects trhough Marshal problem

> Marshal retains an idea of identity only during _one_ write operation.
>  So it will reconstruct graphs properly if you ensure all interesting
> instances are referenced from a single instance.

 I can now clearly see what you say.

> As Hans said: do it in one step for example by placing both in an Array:
>
> irb(main):016:0> x, y = Marshal.load(Marshal.dump([a,b]))
> => [#<A:0x802ba284 @var_a=50>, #<B:0x802ba248 @var_b=#<A:0x802ba284
> @var_a=50>>]
> irb(main):017:0> x.equal? y.var_b
> => true

 Yes, it's what I say above

> In your case it would also be sufficient to only marshal b because
> that references a already and there is an easy way to access it after
> deserialization.

 I understand what you say, but my model is far more complex, I have
many objects with atributtes pointing to anothers objects from
differents clases, it's not so simple. At now the only way that I see
is: in some way try to reconstruct the objects manually, for example,
many of my classes will have only one instance at time in the model, so
I can do something like this(referencing the above example):

-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-

 #supposing that before I've loaded the state of ::A1 which is the state
 #of the above a variable

 #monkeypatch
 class B
  def marshal_dump
   [@var_b]
  end

  #Note: I have all the only-one-instance-per-class pointed by a
  #constant in the main scope(don't know if this is a good way just
  #implemented in that way))
  def marshal_load(attributes)
   @var_b = (if attributes[0].is_a?(A) then ::A1 else attributes[0] end)
  end
 end

-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-

 Do you think that exist a better and faster way than this to treat with
the problem? I'll appreciate your help, thanks.

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