RE: [xml-dev] RE: ANN: Portable Data Component -- start/end

["David Lee" <dlee@calldei.com>]

"Who's at fault"
Anyone who thinks using Time values instead of datetime values for actual
instances of a temporal point is at fault.
Time alone assumes a date is present in the context (either explicitly, or
as an occurrence etc).
Time alone can never specify a temporal point anymore more than an "x" value
alone can specify a point in 2D space or a fraction can specify a decimal.







----------------------------------------
David A. Lee
dlee@calldei.com
http://www.xmlsh.org

-----Original Message-----
From: Costello, Roger L. [mailto:costello@mitre.org] 
Sent: Monday, April 18, 2011 2:19 PM
To: xml-dev@lists.xml.org
Subject: [xml-dev] RE: ANN: Portable Data Component -- start/end


Hi Folks,

Suppose that a person records the start time and end time of a movie, which
starts at 11pm and ends at 1am the next day:

    <movie>
        <start>23:00:00</start>
        <end>01:00:00</end>
    </movie>

Validating that against the portable start/end data component (see below)
results in this error: "movie does not match the assertion".

Had the movie times been specified using dateTime:

    <movie>
        <start>2011-04-16T23:00:00</start>
        <end>2011-04-17T01:00:00</end>
    </movie>

then there would be no error.

QUESTION

Who's at fault? 

    - The person who specified the movie times using just time values? 
    - Or, the portable start/end data component for throwing an error on
perfectly good movie times?

/Roger

P.S. Here's the portable start/end data component:

    <xs:complexType name="start-end-date-time">
        <xs:sequence>
            <xs:element name="start">
                <xs:simpleType>
                    <xs:union memberTypes="xs:date xs:time 
                                           xs:dateTime" />
                </xs:simpleType>
            </xs:element>
            <xs:element name="end" minOccurs="0">
                <xs:simpleType>
                    <xs:union memberTypes="xs:date xs:time 
                                           xs:dateTime" />
                </xs:simpleType>
            </xs:element>
        </xs:sequence>
        <xs:assert test="
              if (exists(end)) then 
                  if (start castable as xs:dateTime) then
                      xs:dateTime(end) gt xs:dateTime(start)
                  else if (start castable as xs:date) then
                      xs:date(end) gt xs:date(start)
                  else if (start castable as xs:time) then
                      xs:time(end) gt xs:time(start)
                  else true()
              else true()" />
    </xs:complexType>

Comments welcome.

/Roger

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