From: dblack@...
Date: 2003-03-24T23:06:23+09:00
Subject: Re: Types (was Re: Ruby lecture slides (was Strong advantages over Python))

Hi --

On Mon, 24 Mar 2003, Jim Freeze wrote:

> On Monday, 24 March 2003 at 16:33:35 +0900, Dave Thomas wrote:
> >
> > Take this example:
> >
> >    class Fred
> >      def shout
> >        puts "wilma"
> >      end
> >    end
> >
> >    f = Fred.new
> >
> >    o = Object.new
> >    def o.shout
> >      puts "wilma"
> >    end
> >
> > 'f' and 'o' have different classes (Fred and Object respectively) but
> > they have indistinguishable types (for all intents and purposes). In
>
> Thanks for the fine example, but for those of us who are a little slow,
> what exactly are the types of 'f' and 'o'?

My characterization of those types, if I had to provide one, would be
something like: respondent to "shout".  Of course that kind of
circular description doesn't scale well in the face of a more
extensive set of methods, which I think is one reason why the idea of
type is inadequate to the task of telling us much about Ruby objects.


David

-- 
David Alan Black
home: dblack@superlink.net
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav