From: Edgardo Hames <ehames@...>
Date: 2004-10-06T04:25:25+09:00
Subject: Re: A ruby course

On Wed, 6 Oct 2004 04:18:17 +0900, Brian Schr�der
<ruby@brian-schroeder.de> wrote:
> Edgardo Hames wrote:
> > On Wed, 6 Oct 2004 02:24:12 +0900, Brian Schr�der
> > <ruby@brian-schroeder.de> wrote:
> >
> >>Anybody has an idea for an exercise on extending existing classes. So
> >>far the only thing I have come up with is:
> >>
> >
> >
> > Taken from the Design Patterns book, Decorator pattern:
> >
> > "Attach additional responsibilities to an object dynamically.
> > Decorators provide a flexible alternative to subclassing for extending
> > functionality."
> >
> > You could extend Integer with a fibonacci method, so that you can
> > write something like:
> >
> > puts 0.fibonacci       > 0
> > puts 1.fibonacci       > 1
> > puts 5.fibonacci       > 5
>
> Should be 12, shouldn't it?

0.fib  > 0
1.fib  > 1
2.fib  > 1
3.fib  > 2
4.fib  > 3
5.fib  > 5

> I'm sorry, but this was exactly the example I gave. It seems we have a
> similar mindset ;)

I'm really sorry, I must admit I didn't really paid much attention to
the example. I'm replying messages while in a training session... :(

But anyway, you can think of the Visitor or Decorator pattern, for
extending classes. Did I mention adding a fib method to Fixnum? ;)

Regards,
Ed

-- 
" Don't relax!  It's only your tension that's holding you together."