From: Paul McMahon <pm@...>
Date: 2007-09-05T11:08:21+09:00
Subject: Re: where is Enumerable#each_cons()?

Try requiring enumerator.

irb(main):001:0> require "enumerator"
=> true
irb(main):002:0> (1..10).each_cons(2) {|a| p a}
[1, 2]
[2, 3]
[3, 4]
[4, 5]
[5, 6]
[6, 7]
[7, 8]
[8, 9]
[9, 10]
=> nil