The Timing of Time

Alan Lovejoy squeak-dev.sourcery at forum-mail.net
Wed Apr 19 01:51:21 UTC 2006


Ralph: "Date is a basic abstraction.  Getting it right is important, and so
far we (the entire programming community) haven't gotten it right."

Yes, exactly so. And the issue is becoming more important, not less, due to
the ever-shrinking "global village."  How many decades remain before the
issues become interplanetery, and not just international, is an interesting
question to ponder (I've considered the implications of interplanetary
travel for date/time software, but haven't put much effort or code into any
solutions yet--that might be premature at this point.)

When all is said and done, it's usually the case that a lot more has been
said than done.  That's one reason I implemented Chronos according to my
best understanding of how dates/times ought to work, instead of attempting
to socialize a consensus in the Smalltalk community for the design of a
date/time library.  A picture of herding cats comes to mind. Or a camel.

Nevertheless, one can always learn from others.  In fact, I would greatly
appreciate feedback on the design/implementation/API of Chronos.  I'm sure
that Hernan, Brent and David T. would like feedback on their work also.

Ralph: "You guys ought to write papers on your Date packages. Someone ought
to write a paper comparing them."

Ayup.  In fact, I've decided to put a halt to coding Chronos and start
writing documentation.  John Dougan and I started to write a paper several
months ago about the model of time on which the Chronos architecture, design
and implementation rests, but we both got sidetracked on/by other matters.

It's "time" to put the theoretical/philosophical discussion back on the
front burner. As for comparisons of the alternatives on offer, that's a job
best left to some independent analyst, I would think.

--Alan

-----Original Message-----
From: squeak-dev-bounces at lists.squeakfoundation.org
[mailto:squeak-dev-bounces at lists.squeakfoundation.org] On Behalf Of Ralph
Johnson
Sent: Tuesday, April 18, 2006 5:38 PM
To: The general-purpose Squeak developers list
Subject: Re: The Timing of Time

It is interesting to me 1) how much interest there is in dates and 2) how
apologetic people seem to be about it.  Date is a basic abstraction.
Getting it right is important, and so far we (the entire programming
community) haven't gotten it right.  Discussions like this are important.
You guys ought to write papers on your Date packages.
Someone ought to write a paper comparing them.

Maybe Maxi Taborda is going to do this for his MS thesis?

My favorite book on calenders (I haven't read very many) is "Calendrical
Calculations" by Reingold and Dershowitz.  It is about dates and not time.

-Ralph Johnson





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