From: David Masover <ninja@...>
Date: 2010-04-26T05:23:40+09:00
Subject: Re: DrX, an object inspector

On Sunday 25 April 2010 02:41:07 am Charles Oliver Nutter wrote:
> On Sat, Apr 24, 2010 at 10:38 AM, David Masover <ninja@slaphack.com> wrote:
> >> For getting the data, you don't even need to write an extension to
> >> JRuby. The "jruby" library gives you introspective access to all
> >> objects at a very direct level:
> >
> > It seems like this should be possible to do from bare Ruby, in a portable
> > way. Clumsy, but possible. For example, as long as people don't get smart
> > and use Ruby 1.9's BasicObject, you can do this:
> 
> No, I'm pretty sure this isn't possible on regular Ruby.

Ah, wishful thinking of my part, then.

> What's
> happening in JRuby is that you're getting direct access to the Java
> object representing a Ruby class or object, and you then can do
> anything to that object you'd normally have to write Java code for.

I've raised this question before, and people seem to disagree with me, but:

> # changing the object's class(!?)
> class Foo; end
> p obj.class # => 'Object'
> obj_ref.setMetaClass(JRuby.reference(Foo))
> p obj.class # => 'Foo'

I think it should be possible to do that from within Ruby.

But I can't even get most people behind this suggestion:

class A; end
class B; end
A.instance_method(:to_s).bind(B.new)

That gives me a type error, which just seems bizarre, especially after the 
relative freedom of JavaScript. Ah, well.