From: Matt Todd <chiology@...>
Date: 2006-08-13T18:31:07+09:00
Subject: Re: A use case for an ordered hash

Absolutely... an Array is perfect for ordered information.

actions = [
  { /abcd/ => lambda { do_this } },
  { /xyz/ => lambda { do_that } },
  { /abc/ => lambda { other } }
]

Then, all you do is...

actions.select { |action| action[input] }

where input = /xyz/ you will receive the appropriate hash (key and
Proc) in an array. So, to do something with that, you could...

actions.select { |action| action[input] }.first[input].call

which calls the Proc associated with the matching element.

I'm not too thrilled with its convolutedness, and I'm sure there's a
better way, but I'm pretty sleepy, so this is the best I'm coming up
with right now. :) As always, you can write a method to hide the gory
details.

def exec_route input
  actions.select { |action| action[input] }.first[input].call
end

and just call:

exec_route /xyz/

and blam! do_that is executed!

Hope this helps.

M.T.