From: Szabolcs Szasz <sz@...>
Date: 2002-10-20T11:28:27+09:00
Subject: Re: Is subclass known in superclass.initialize? (virtual constructor theme...)

I did start with the class/type method, but still only saw the 
superclass in the constructor... Strange, I must have missed 
something subtle in the actual code (which is different from 
my gutted example below).

Needless to say, now it does work just fine in the original 
code, too... 

Well, it can be a bit frustrating to be a newbie sometimes... ;)

Thanks very much,
Sab

----- Original Message ----- 
From: "Dave Thomas" <Dave@PragmaticProgrammer.com>
To: "ruby-talk ML" <ruby-talk@ruby-lang.org>
Sent: Sunday, October 20, 2002 4:07 AM
Subject: Re: Is subclass known in superclass.initialize? (virtual constructor theme...)


> "Szabolcs Szasz" <sz@szasz.hu> writes:
> 
> > Is there a reasonable replacement for '?' below?
> > 
> >     class Super
> >         def initialize
> >             sub = '?'    # something that yields obj.class
> >             puts "Created for subclass #{sub}"
> >         end
> >     end
> 
> 'type' returns the class of its receiver, so:
> 
>    class Super
>      def initialize
>        sub = type
>        puts "Created for subclass #{sub}"
>      end
>    end
> 
>    class Sub < Super
>    end
> 
>    obj = Super.new    #=> Created for subclass Super
>    obj = Sub.new      #=> Created for subclass Sub
> 
> 
> So can also use #class, but you have to be careful to call it with an
> explicit receiver, or Ruby will think you're starting a class
> definition.
> 
> 
> Cheers
> 
> 
> Dave
> 
>