From: Jeff Mitchell <quixoticsycophant@...>
Date: 2004-06-06T05:12:53+09:00
Subject: Re: How to ducktype a Hash?


--- Sean O'Dell <sean@celsoft.com> wrote:
> On Saturday 05 June 2004 10:39, Dave Thomas wrote:
> > On Jun 5, 2004, at 12:30, Sean O'Dell wrote:
> > > I just don't like this duck-typing business.  I can handle dynamic
> > > typing, but
> > > I wish there were something more solid about the typing, at least a
> > > way to
> > > know when an object implements a certain interface or not, so I can
> > > tell an
> > > array-like object from a hash-like object.
> >
> > Perhaps you could design the interface to your classes so that the
> > distinction is either explicit or irrelevant.
> 
> It's not my classes that are the problem, it's all of the other objects that 
> respond to [] and []=, but which aren't hash-like (they're array-like, and 
> even then it's anyone's guess as to the functionality).

Could you use explicit names such as #lookup and #store ?  I realize it's
not as convenient as [], but the problem is that [] is overloaded with meaning.
Perhaps that's what Dave is suggesting.

Thus you'd add #lookup and #store to Hash and all things Hash-like.
With these explicit names you can duck-type without running into geese
and other imposters.



	
		
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