From: David D'Andrea <david.dandrea@...>
Date: 2003-11-12T05:43:50+09:00
Subject: Re: Ruby/Tk Some Basic Questions

I got this reply from Lyle Johnson (thanks), so just in case anyone 
else was wondering:

 > Yes, your guess is correct. Abstract base classes are never themselves
 >  instantiated, but rather provide a set of basic functionality that 
their
 > (concrete) subclasses use.

I suppose there's no way to enforce the non-instantiation of these 
abstract classes, you just don't unless you're feeling perverse.

(me never, really!)

David

On Tuesday, November 11, 2003, at 01:44  PM, Zach Dennis wrote:

> I think that is a good question!!
>
> I know an abstract class in Java, and I just figured the same thing 
> applied
> here in a ruby-ish way, but I was pondering the exact same question! 
> What is
> an abstract class in Ruby?
>
> Zach
>
> -----Original Message-----
> From: David D'Andrea [mailto:david.dandrea@sympatico.ca]
> Sent: Tuesday, November 11, 2003 1:05 PM
> To: ruby-talk ML
> Subject: Re: Ruby/Tk Some Basic Questions
>
>
> If you'll forgive another newbie question:
>
> What is an abstract class?
>
> I think of classes as abstract already, and objects as concrete.  Maybe
> an abstract class is one that never gets instantiated, but is always
> further specified / subclassed before being used?
>
> David
>
> On Monday, November 10, 2003, at 08:49  PM, Hidetoshi NAGAI wrote:
>
>> Hi,
>>
>> From: "Zach Dennis" <zdennis@mktec.com>
>>> I am wondering if there is a
>>> major difference between TkRoot and TkWindow and it might be. In all
>>> of the
>>> ruby examples folks use TkRoot and assign all widgets to it, but the
>>> TkWindow still exists. So why use one over the other?
>>
>> TkWindow class is an abstract class.
>> --
>>                                   Hidetoshi NAGAI
>> (nagai@ai.kyutech.ac.jp)
>>
>
>
>
>