[ruby-talk:02274] Re: Adding method to Object -- Why doesn't this work?

Thanks much, Dave!

I'm a little in the dark about singleton methods. I'm 
not sure when one would use one instead of an instance
method.

BTW< That must be some kind of record for a speedy 
response. If you had been any faster, I would have 
received the reply before I asked the question. Are 
you using a time machine?

I had actually thought it might be hours till I got
an answer... most of the people on this list are asleep
right now, aren't they? 

Hal

> [e-mail] writes:
> 
> > Greetings, fellow Ruby enthusiasts.
> > 
> > Perhaps I have a fundamental misunderstanding here.
> 
> Perhaps.. ;-)
> 
> When you defined Object.foobar, you're creating a singleton method in
> Object (one that should be called as Object.foobar), not an instance
> method. Thus the method is not available through a message to self.
> 
> So, you could rewrite it as an instance method, and all's fine. (I
> also used the wonderful 'defined?' expression to check for foorbar in
> a superclass.
> 
> class Object
>   def foobar
>     print "I am the ultimate foobar!\n"
>   end
> end
> 
> class Foo
>   def foobar
>     print "I am Foo::foobar... "
>     if defined? super
>       print "my parent has a foobar!\n"
>       super
>     else
>       print "my parent does NOT have a foobar.\n"
>     end
>     print "My parent is ", self.type.superclass, "\n"
>   end
> end
> 
> Foo.new.foobar
> 
> -- 
> Thomas Consulting.
> Innovative and successful developments with Unix, Java, C, and C++. 
> 
> Now in bookstores:
>  The Pragmatic Programmer.  www.pragmaticprogrammer.com/ppbook/