[ruby-talk:02072] Re: Anonymous and Singleton Classes

Re: [ruby-talk:02062] Re: Anonymous and Singleton Classes

Matz,
  thanks for explaining this stuff to me, I'm sure that you must have explained
it enough before.

> Hmm, there was discussion about this matter before, without explicit
> conclusion.  Let's talk it again.  What should we call `class <<obj'
> statement?

As it contains the keyword 'class' I think that it will be difficult to try and
hide the fact that it is a class type operation.  I spent a lot of time
worrying about what wasn't being said and what was hinted at, FAQ 6.6's use of
'anonymous class' suggests parallels with Class::new() and the description of
super() in the FAQ talks of calling the method in the superclass which suggests
an inheritance relationship.

I think that 'singleton class' is fine, I just needed more help in coming to
terms with something that was so unfamiliar.  I am used to modifying the
behaviour of objects of the same class by supplying different
parameters/attributes, not by overriding complete operations.  Overriding to me
feels like an inheritance thing.

>I'm not sure how much I should describe implementation details.
>Conceptually, a class inherits singleton methods also from its
>superclass.  That's all.
>
>In current implementation, they are done by internal hidden class
>called `singleton class', which is real class of classes.  You can
>consider this hidden class a metaclass.  Better description is welcome.

That's fine by me.  I just got curious and a little confused when you talked
about the class of a class being a metaclass when MyClass.type returned Class. 
It took me a while to make the connection with the effects of adding singleton
methods or creating a singleton class.


>  def Class.inherited(c)
>    ...
>  end
>
>defines a class method of Class, which is shared by subclasses of
>Class.  C1 is a instance of Class, but not a subclass of Class. So you
>should have
>
>  class Class
>   def inherited(c)  # override default `inherited'
>     ...
>   end
>  end

Sorry about this one.  I realised what was going on shortly after posting the
message.


> By the way, how many times did I type `class' in this mail? :-)
>
>							matz.

I know how you feel.

.../Bob

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