From: "S. Robert James" <srobertjames@...>
Date: 2007-02-24T04:55:05+09:00
Subject: enum_cons with tail

enum_cons chops off the tail of the collection, if it isn't evenly
divisble:

e.g.:
    (1..10).each_cons(3) {|a| p a}
    # outputs below
    [1, 2, 3]
    [2, 3, 4]
    [3, 4, 5]
    [4, 5, 6]
    [5, 6, 7]
    [6, 7, 8]
    [7, 8, 9]
    [8, 9, 10]

I'd also like to get:
[9, 10, nil]
[10, nil, nil]

Is there anyway to do this?  (The collection is an opened File, too
large to load entirely in memory.)

I don't have a clear grasp as to how internally Ruby treats a File as
Enumerable.