From: dblack@...
Date: 2006-03-27T22:00:13+09:00
Subject: Re: Duck typing bunches of strings

Hi --

On Mon, 27 Mar 2006, listrecv@gmail.com wrote:

> In my quest to master the fine art of duck typing / overloading, I've
> run into this probem:
>
> How can I identify a collection?
> The problem is: String mixes in Enumerable, although it ain't a
> collection.
>
> My method wants to act differently if it's given a collection, then if
> it's just given a single object.  I would check .respond_to? :each -
> but String does, unfortunately.
>
> Currently, I'm forced to do .kind_of? Array - but this ain't duck
> typing.
>
> Any ideas?  I'd like to separate Array, Hash, Set, etc. etc. from
> single member objects.

If you really want to do duck typing in your method, then you would
need to prepare the objects in advance, by having them learn a
particular method, probably via an extend operation.  Then your method
can just ask each object to execute its version of that method.


David

-- 
David A. Black (dblack@wobblini.net)
Ruby Power and Light, LLC (http://www.rubypowerandlight.com)

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