Re: [Caml-list] Smells like duck-typing

[Stefano Zacchiroli <zack@bononia.it>]

On Thu, Oct 18, 2007 at 11:31:34AM +0100, Dario Teixeira wrote:
> >   class full (id, title, intro, body) =
> >   object
> >           inherit blurb (id, title, intro)
> >           method body: string = body
> >   end
> 
> While that would indeed involve a little bit of less typing, it's also
> conceptually wrong, because a Full story is not a derivation of a Blurb
> with an extra field.

Well, remember that in ocaml inheritance is not an instance of "is a"
relationship among classes, but rather "method inclusion" (if you really
want a name for this :)). So you can imagine that blurb (or call it
otherwise) is just a set of methods denoting how a blurb-like class
should behave, and here you have back the duck-typing mentioned in the
subject, and than you "inherit" from it both in the actual blurb class
and in the full class.

Just my 0.02€,
Cheers.

-- 
Stefano Zacchiroli -*- PhD in Computer Science ............... now what?
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