From: "Ara.T.Howard" <ahoward@...>
Date: 2004-06-26T00:03:05+09:00
Subject: Re: Is it considered Harmful?

On Fri, 25 Jun 2004, Jim Weirich wrote:

>
> Scott Rubin said:
>> I can't possibly imagine it being useful to do this except when the
>> objects have very similar, if not identical, instance variables.
>
> The "standard" application for the self.class= method (aka become(class))
> is use it to do demand on load style proxies.  Suppose you have a largish
> object in external storage (database, file, whatever).  You create a
> small, efficient proxy item for the large object until you really need the
> true data in the object.  Then you load the object and let the proxy
> "become" the newly loaded object.
>
> Without class=/become methods,
> (a) the proxy remains and forwards all messages to the real object, or
> (b) you replace every reference in the program to the proxy with
>  a reference to the real object.
>
> (a) is a small, but anoying constant cost, and (b) may be difficult,
> depending on how wide spread the proxy was used.
>
> That's why class=/become would be attractive, despite its technical
> difficulties and mildly worrisome semantices.
>
> --
> -- Jim Weirich     jim@weirichhouse.org    http://onestepback.org
> -----------------------------------------------------------------
> "Beware of bugs in the above code; I have only proved it correct,
> not tried it." -- Donald Knuth (in a memo to Peter van Emde Boas)

sounds like an RCR for Object#tie

-a
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