Misuse of period facet in section 3.3.17 Datatypes in Nov 5 WD

3.3.17 date
[Definition:] The date datatype represents a timeDuration (§3.2.5) that starts at midnight of a specified day and lasts for 24 hours. The basetype of date is recurringInstant (§3.2.6). date is generated from recurringInstant (§3.2.6) by setting the value of the period facet equal to 24 hours. 

This seems to describe the Groundhog Day scenario where a specific day repeats itself over and over.  The period of a date should always be greater than 24 hours.  If the date was to represent the 15th of every month, the period would be 1 month.  If the date was to represent April 15th of every year, the period should be one year.

The use of the date datatype is not consistent with the definition of timeDuration which is to indicate a length of time (from the example in 3.2.5.1, 1 year, 2 months, 3 days, 10 hours, and 30 minutes).  date seems to be most directly related to the Time Period concept introduced in 3.2.5.1 but not given any expression.

Maybe the cleanest way to resolve this is to add a resolution facet to timeInstant.  Then date would be timeInstant with a resolution of 24 hours (with trunctation semantics).

<!--  one specific date  -->
<datatype name="date">
<basetype name="timeInstant"/>
<resolution>1T00:00:00</resolution>
</datatype>

A yearly date would be a recurring instant with a period of one year and a resolution of 24 hours.

<!--  one date each year -->
<datatype name="yearlyDate">
<basetype name="recurringInstant"/>
<resolution>1T00:00:00</resolution>
<period>0001-00-00</period>
</datatype>

<!--  one date each month -->
<datatype name="monthlyDate">
<basetype name="recurringInstant"/>
<resolution>1T00:00:00</resolution>
<period>0000-01-00</period>
</datatype>

<!--  one calendar month -->
<datetype name="month">
<basetype name="recurringInstant"/>
<resolution>0000-01-00</resolution>
<period>0001-00-00</period>
</datatype>


----------------------------------------------------------------
Get your free email from AltaVista at http://altavista.iname.com

Received on Monday, 8 November 1999 14:31:45 UTC