From: "F. Senault" <fred@...>
Date: 2007-03-15T05:55:14+09:00
Subject: Re: Calculating the age given DOB

Le 14 mars 2007 � 20:50, Pit Capitain a �crit :

> F. Senault schrieb:
>>>> (d1.year - d2.year) - (d1.yday >= d2.yday ? 0 : 1)
> 
> Pardon Fred, using #yday would be short and nice, but this doesn't work 
> reliably if one year is a leap year and the other is not. 

Yup, you're perfectly right.  The following version seems to work, but
we're steadily losing elegance...  :)

>> d1 = Date.new(2007, 3, 1); d2 = Date.new(2004, 3, 1)
=> #<Date: 4906131/2,0,2299161>
>> (d1.year - d2.year) - (d1.yday >= Date.new(d1.year, d2.month, 1).yday + d2.day - 1 ? 0 : 1)
=> 3
>> d1 = d1 - 1
=> #<Date: 4908319/2,0,2299161>
>> (d1.year - d2.year) - (d1.yday >= Date.new(d1.year, d2.month, 1).yday + d2.day - 1 ? 0 : 1)
=> 2

A pity Date.new doesn't handle overflows.  I'd like to be able to write
this :

>> Date.new(2007, 2, 29).to_s
=> '2007-03-01'
>> Date.new(2007, 3, 0).to_s
=> '2007-02-28'

Fred
-- 
And there shall be no more red roses, but only white, for she has 
squeezed the blood of all living things into her cup.
                                                      (Aleister Crowley)