From: Gary Wright <gwtmp01@...>
Date: 2008-02-14T05:27:57+09:00
Subject: Re: ruby wish-list


On Feb 13, 2008, at 2:56 PM, Roger Pack wrote:
> or maybe not even use brackets at all--they confuse with their
> similarity to arrays.
> Thoughts?

I tend to define [] and []= whenever possible if the object behaves  
like an indexed collection of objects.  I think this helps with duck- 
typing.  If every collection had a different manner of indexing items  
it would defeat any duck-typing.

Less common, but also useful is to provide fetch/store in addition to  
[] and []=.  The fetch API is nice when you want to substitute a  
different default value:

  fetch(index)        # get item or raise exception
  fetch(index, miss)  # get item or return miss
  fetch(index) { }    # get item or compute miss

Gary Wright