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Re: xml.com piece on XML Schema datatypes (no rationals :-{)

From: Dan Connolly <connolly@w3.org>
Date: 01 Aug 2002 17:51:12 -0500
To: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
Cc: Dan Brickley <danbri@w3.org>, w3c-rdfcore-wg@w3.org
Message-Id: <1028242272.28235.46.camel@dirk>

On Thu, 2002-08-01 at 16:29, Graham Klyne wrote:

> My own particular pet peeve with XML schema datatypes is the lack of a 
> rational number primitive (my comment was submitted to, considered and 
> rejected by XML schema WG).

Sorry about that; I agree, but I didn't have the energy to fight harder.
I did put the HTTP-NG type system on the table, which had a nice
design for rationals (hm... reviewing, it seems to be fixed-point,
not rationals... anyway...). Sigh.

>  To my view, this should be the concept from 
> which all other numeric data types are derived, by restriction.  (All 
> schemes for representing numbers in a computer that I'm aware of represent 
> rational numbers only.)

Well, floating point numbers are not restrictions of rationals.
Floating point multiplication and addition are not, strictly
speaking, associative.

There's a great piece on that in the proceedings of the WG...

(searching, I find one of my contributions...

Aha! there it is:

		Floating-point datatypes are not real datatypes
			Mark Reinhold <mr@eng.sun.com>
				5 October 1999

> I've no objection that RDF should be able to use XML schema datatypes, but 
> I already know of applications where they aren't enough.  CONNEG uses 
> rational numbers, and we're working to make CONNEG vocabulary accessible to 
> CC/PP.

Dan Connolly, W3C http://www.w3.org/People/Connolly/
see you in Montreal in August at Extreme Markup 2002?
Received on Thursday, 1 August 2002 18:50:47 UTC

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