- From: by way of <staschuk@telusplanet.net>
- Date: Tue, 24 Dec 2002 11:28:49 -0700
- To: W3C XML Schema Comments list <www-xml-schema-comments@w3.org>
Time durations are added by simply adding each of their fields, respectively, without overflow. [_Part 2: Datatypes_, section E.2] Consider "P1Y" + "-P1D". Prior to the clarification of erratum E2-23, we might think this results in "P1Y-1D", one day less than a year. However, now it is clear that durations are not closed under addition. Closure under addition is a useful enough property that I'd like to see in 1.1 a duration-like type which has it. The only difference between the two types would be the admission of signs on a component-by-component basis. Such a type being defined, it would seem most natural to reformulate the existing duration type as a derivation-by-restriction of the new type; but I imagine there are some backwards-compatibility issues to be considered. (In the meantime, of course, implementations can use pairs of durations, one positive and one negative, for arithmetic purposes.) -- Steven Taschuk | w_w staschuk@telusplanet.net | ,-= U | 1 1 Moose
Received on Tuesday, 24 December 2002 14:15:11 UTC