From: Gary Wright <gwtmp01@...>
Date: 2009-11-20T09:49:57+09:00
Subject: Re: Any official name for Ruby's class which makes "class me


On Nov 19, 2009, at 5:50 PM, David A. Black wrote:
> On Fri, 20 Nov 2009, Florian Frank wrote:
>
>> David A. Black wrote:
>>> The metaclasses are anonymous. The metaclass (or whatever we call  
>>> it)
>>> of String, for example, is a completely separate class/object from
>>> String:
>>
>> Yes. And these things, that shall never be named, aren't much like
>> classes either: They cannot create any instances for example. In Ruby
>> terminology they are much closer to modules in the sense, that they  
>> are
>> containers of methods, that are used to extend objects.
>
> I could definitely imagine 'singleton module' instead of 'singleton
> class'. I think Matz has commented on this choice but I can't remember
> any details.

I was thinking along the same lines while reading this thread. There  
are a few characteristics that seem to argue for class implementation  
vs a module implementation:

-- the class/instance relationship doesn't have an analog
    with modules and an object can be viewed as an "instance"
    of its singleton class

-- the inheritance relationship of classes provides a
    structure for searching singleton classes of classes that
    also no analog with modules

These aren't strong reasons for a class implementation over a module  
implementation but it seems like a module implementation would involve  
adding special case semantics to the 'singleton modules' that aren't  
as 'special' in the current singleton class implementation.

Gary Wright