- From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
- Date: Tue, 31 Jul 2012 15:36:14 -0400
- To: David Booth <david@dbooth.org>
- CC: public-rdf-comments <public-rdf-comments@w3.org>
Hmm. Your two examples have different canonical forms in XML. I do not believe that going beyond XML canonicalization is a good idea. I find your request for a second canonical form for XML datetime to be rather strange. Isn't it a major point of a canonical form that there is only one? In any case, I don't see the point here. If equality-unique canonical forms are only encouraged, then applications will still have to do datatype-aware comparisons. peter On 07/31/2012 02:31 PM, David Booth wrote: > 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". > >
Received on Tuesday, 31 July 2012 19:36:42 UTC