From: Caleb Clausen <vikkous@...>
Date: 2009-05-02T01:52:29+09:00
Subject: Re: Finding Matches in Array of Classes

Joel's select/include? implementation is the normal way to solve this
particular problem, but if you're looking for a more general approach
to dealing with arrays and other ruby data structures, you might look
at Reg, my declarative language for matching ruby data structures.
With Reg, I would use this variation on Joel's code:

require 'rubygems'
require 'reg'
require 'time'

range = Time.parse("2008-1-1")...Time.parse("2009-1-1")
#results.select {|r| range.include? r.observation_time}
results.grep -{:observation_time=>range}

For most things Reg can do, it's syntax is shorter than the equivalent
imperative form, but it's not so big in simple cases like this.

http://rubyforge.org/projects/reg/
http://github.com/coatl/reg/