From: Stephen Bannasch <stephen.bannasch@...>
Date: 2007-09-18T10:43:38+09:00
Subject: Re: [?] problem using set with hash objects

Ribert, Stefano, and Jano, thanks for the pointers.

I'm now using "ara.t.howard" <ara.t.howard@gmail.com>'s arrayfields 
gem to get hash like access to my data structures stored in arrays. 
This combines well with set. Here's an example:

$ sudo gem install arrayfields

$ cat a.rb
require 'set'
require 'arrayfields'
abc = Array.struct :a, :b, :c
a = abc.new [1,2,3]               # => [1, 2, 3]
b = abc.new [1,2,3]               # => [1, 2, 3]
c = abc.new [4,5,6]               # => [4, 5, 6]
p a[:a]                           # => 1
p c[:a]                           # => 4
p a1 = [a,b,c]                    # => [[1, 2, 3], [1, 2, 3], [4, 5, 6]]
p b1 = a1.to_set.to_a             # => [[1, 2, 3], [4, 5, 6]]
p b1[0][:a]                       # => 1
p b1[1][:c]                       # => 6

$ ruby a.rb
1
4
[[1, 2, 3], [1, 2, 3], [4, 5, 6]]
[[1, 2, 3], [4, 5, 6]]
1
6