- From: David Booth <david@dbooth.org>
- Date: Tue, 31 Jul 2012 14:31:41 -0400
- To: public-rdf-comments <public-rdf-comments@w3.org>
To enable RDF from one system to be more easily compared with RDF from another system, it would be helpful if the serialization of datatyped literals were encouraged to be in a canonical form that would enable simple string comparison to be used instead of requiring a comparator that understands the semantics of each datatype. A particular case in point: xsd:datetime. "2012-07-31T17:16:00+01:00"^^xsd:dateTime represents the same point in time as "2012-07-31T16:16:00Z"^^xsd:dateTime but the strings are not the same. This could be avoided by encouraging a canonical serialization such as dateTimeStamp http://www.w3.org/TR/xmlschema11-2/#dateTimeStamp in which the timezoneFrag is required to be "Z". (I've just filed a bugzilla report on XML Datatypes to ask for such a canonicalization https://www.w3.org/Bugs/Public/show_bug.cgi?id=18452 because there doesn't seem to be one defined currently.) How forcefully such canonicalization should be encouraged is a matter for debate. I do not think it should be a "MUST". "SHOULD" would be fine, as there are good reasons why someone may want to generate non-canonical literals. But it may also be good enough to just put an editorial note in the spec saying that "RDF generators are encouraged to generate literals in a standard, canonical form that allows simple string comparison to test for equality and greater-than/less-than when possible". -- David Booth, Ph.D. http://dbooth.org/ Opinions expressed herein are those of the author and do not necessarily reflect those of his employer.
Received on Tuesday, 31 July 2012 18:32:14 UTC