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From: kilgallen@eisner.decus.org (Larry Kilgallen)
Subject: Re: Calling C time function from ADA-95
Date: 1998/06/12
Message-ID: <1998Jun11.211003.1@eisner>#1/1
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References: <3579da75.13533758@enews.newsguy.com>
 <357C141E.D868661F@earthling.net> <6lhnan$1vi$1@goanna.cs.rmit.edu.au>
 <357D166E.685D7A09@cl.cam.ac.uk> <357D5083.45CB71F1@earthling.net>
 <357D6F53.46486039@cl.cam.ac.uk> <357DA2E1.704E9A16@earthling.net>
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Date: 1998-06-12T00:00:00+00:00
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In article <357DA2E1.704E9A16@earthling.net>, Charles Hixson <charleshixson@earthling.net> writes:
> Sure, it could easily be based on floating point numbers.  And yes, I
> can write my own calendar package.  Everybody seems to end up needing to
> write their own calendar.  But doesn't that sort of defeat the purpose
> of a system library?  Everyone could write their own sine_table package,
> too, but the system routine, being good enough, almost nobody does.  If
> people are needing to re-implement the calendar, then that's a sign that
> the calendar package ... well, broken usually means something else.

But computers should model the real world, and governments have diverged
in their definitions of the calendar.  If you write a package it will work
back to the year 1000 for everyone who agrees with your choice of which
government standards to use during which periods.  I might choose another.

Of course, like the folks who don't care about leap-seconds, you will
gather a larger constituency if you convince people that 12 days of
divergence does not matter in the greater scheme of things.

For those who really care about dates 300 years ago, however, it does
matter which calendar system is to be honored.  If you want to assume
that the current algorithm just goes back into the past in a regular
pattern, you will satisfy those who want a neat mathematical answer,
but not the needs of those who actually care about the dates in question.

Larry Kilgallen