From: James Moore <banshee@...>
Date: 2006-09-22T05:13:49+09:00
Subject: Re: Calculate last day of month

>      d += 42                  # warp into the next month

You need to add a month, not a fixed number of days, since you can't predict
how many days are in the next month:

irb(main):033:0> d = Date.new 2006, 1, 31
=> #<Date: 4907533/2,0,2299161>
irb(main):034:0> (d >> 1).to_s
=> "2006-02-28"


irb(main):039:0> d = Date.new 1996, 1, 31
=> #<Date: 4900227/2,0,2299161>
irb(main):040:0> (d >> 1).to_s
=> "1996-02-29"

 - James Moore