From: Trans <transfire@...>
Date: 2005-12-10T02:02:36+09:00
Subject: Re: ordered/sorted hash

Okay, I have preliminary implementation of Dictionary class with
built-in ordering. Its important to note that the implementation isn't
as efficient as sorting externally b/c the class sorts the pairs *every
time* #each is called (if order_by is set). There are ways to improve
the efficiency, but that's a task for another day.

The basic way to do it:

  d = Dictionary.new.order_by{ |k,v| k }

This creates a dictionary orderd by the key. The block allows you to
define almost any order mechisim you like. Since alphanumeric key order
is likely the most common (after the default of insertion order) I
created a special constructor method just for it:

  d = Dictionary.alpha

This does the exact same thing is the last example. The only thing I'm
not so sure about is the name of this method. Is this good or would
something else be better?

BTW, Ara, you inspired me:

  d = Dictionary.auto

will do the same as OrderedAutoHash::new. Thanks for that idea. Of
course, I have the same question about my choice of method name here
too.

T.