From: Eric Mahurin <eric_mahurin@...>
Date: 2005-08-19T01:10:42+09:00
Subject: Re: Prototype-based / Ruby question

--- "David A. Black" <dblack@wobblini.net> wrote:
> >> Obviously any given use of an object does not recapitulate
> or
> >> encapsulate its entire type, if "type" is defined as the
> object's
> >> capabilities.
> >
> > And that is why I think this definition of "type" is not
> very
> > useful.  The definition I gave for duck-type is quite
> useful in
> > the context of duck-typing - for documenting arguments of
> > methods.
> 
> I'm not sure how we've gotten onto documentation.  (Yes, I
> know it's
> all part of programming responsibily....)

In ruby, since you don't declare the type of your arguments
anywhere in the code (like you would in a statically typed
languaage), the only place left to discuss the "type" is in the
documentation.  I don't see where else "type" really matters.

> Anyway, if you
> want to
> say: "This method takes an argument whose duck type is 'this
> object
> responds to "x"'", instead of: "This method takes an argument
> that
> responds to 'x'", be my guest :-)  I don't see what it adds. 
> I prefer
> the shorter way.

I prefer the shorter way too.  There is no reason to use the
words duck, type, or a combination of the two, even though you
are clearly duck-typing.  Similarly, when a you declare a
static type to an argument in a statically typed language, you
don't use the words static or type (unless either of those are
needed keywords in the language).



		
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