From: Gavin Kistner <gavin@...>
Date: 2005-02-10T23:47:03+09:00
Subject: Class of the Instance [was Re: Building a Better Functor]

On Feb 10, 2005, at 7:35 AM, Robert Klemme wrote:
> "Gavin Kistner" <gavin@refinery.com> schrieb im Newsbeitrag
> news:991b24e67ac5d4902f4b04192210830a@refinery.com...
>>> Robert Klemme wrote:
>>>>     class << self;self;end.class_eval do
>> Is it to add new methods to the instance only, and not all instances
>> derived from Foo?
>
> Exactly.

Coming from Javascript (where every instance is trivially extensible 
directly) that seems somewhat cumbersome.

Do many people write things like:

class Object
	def instance_class
		class<<self; self; end
	end
end

in a common library they re-use frequently? Is there an RCR (or has 
there been discussion) about adding a simple method like that to the 
language, so you can simply do:

f = Foo.new
f.instance_class.class_eval{ ... }
?

Or (what I'm really looking for) perhaps it might be nice to have a 
define_method method that worked directly for instances. Hrm, but what 
would the syntax be? Perhaps that's not such a good idea.