From: "Mauricio Fernández" <batsman.geo@...>
Date: 2003-02-02T01:35:24+09:00
Subject: Re: Coercion of variables

On Sun, Feb 02, 2003 at 12:38:57AM +0900, Brian Candler wrote:
> A question.
> 
> If I have an object of class "Foo", I know I can change this object into an
> anonymous subclass:
> 
>   obj = Foo.new
>   class <<obj
>     def wibble
>       # whatever
>     end
>   end
> 
>   obj.wibble
> 
> However, suppose I have an existing class hierarchy: Bar is a subclass of
> Foo. I want to convert obj from an instance of Foo into an instance of the
> subclass Bar.
> 
> Is that possible, without creating a whole new Bar object?
> 
> (Practical example: I have defined a subclass of the TCPSocket object.
> TCPServer#accept returns an object of class TCPSocket. I want to convert
> this object into my own subclass)

You can extend that object with features defined in a module to give it
the wanted functionality. Its class won't change, but adding things to
its singleton class you can get the behavior you want.

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	-- Seen on linux-kernel