- From: Kay, Michael <Michael.Kay@softwareag.com>
- Date: Tue, 2 Dec 2003 18:47:47 +0100
- To: David Carlisle <davidc@nag.co.uk>, public-qt-comments@w3.org
- Message-ID: <DFF2AC9E3583D511A21F0008C7E62106073DD30E@daemsg02.software-ag.de>

Thanks, this problem has already been pointed out (by me) and we're looking at it. I have made the suggestion that idiv should be defined on all numeric types. This would mean that [10 idiv xdt:untypedAtomic("2.5")] returns 4, not 5 as it does currently. It would also mean (I think) that the expression [(a idiv b)*b+(a mod b) = a] becomes true for all numeric values a and b. Michael Kay > -----Original Message----- > From: David Carlisle [mailto:davidc@nag.co.uk] > Sent: 02 December 2003 17:20 > To: public-qt-comments@w3.org > Subject: [F&O] 6.2.6 op:numeric-mod > > > > > The description of mod uses expressions the expression > (a idiv b)*b+(a mod b) > that is (one assumes) XPath/Xquery, (although other cases of > explict xpath examples the operators have op: or fn: syntax > so this probably ought to be > op:numeric-multiply(op:numeric-integer-divide(a,b) ,b)... > > > however it also uses the phrase > > the result obeys (a/b)*b+(a mod b) = a. Division is > truncating division, > analogous to integer division, not [IEEE 754-1985] rounding > division. > > The expression there is a valid Xpath, but not the desired > expression:-) I assume that the second sentence is intended > to give a local definition of "/" but > a) I think some other syntax should be used in > preference to "/" to avoid confusion, and > b) I don't think "analogous to integer division" is clear enough as a > specification. > > If a and b are positive I assume you want something > equivalent to the Xpath floor(a div b)*b+(a mod b) = a > Although It's not clear whether mod should be _defined_ that > way in terms of the Xpath floor and div (which may affect > certain edge cases). > > > David > > > ______________________________________________________________ > __________ > This e-mail has been scanned for all viruses by Star > Internet. The service is powered by MessageLabs. For more > information on a proactive anti-virus service working around > the clock, around the globe, visit: http://www.star.net.uk > ______________________________________________________________ > __________ >

Received on Tuesday, 2 December 2003 12:49:09 UTC