Cart
[Home] [By Thread] [By Date] [Recent Entries]
----- Original Message ----- From: "Henry S. Thompson" <ht@c...> To: "Dare Obasanjo" <kpako@y...> Cc: "xml-dev" <xml-dev@l...> Sent: Friday, January 04, 2002 5:05 AM Subject: Re: Question on using xs:pattern to restrict xs:dateTime > > From what I've seen the pattern facet can easily be made to create > > illegal restrictions which none of the validating parsers I have > > tried warns about. > > Um, now I'm confused -- how does your example's use of pattern create > 'illegal restrictions'? I guess "illegal restriction" is the wrong terminology. > > > > <xsd:simpleType name="myTimeType"> > > > > <xsd:restriction base="xsd:dateTime"> > > > > <xsd:pattern value="\d\d:\d\d(:\d\d)?" /> > > > > <xsd:whiteSpace value="collapse" /> > > > > </xsd:restriction> > > > > </xsd:simpleType> > > It's true there are no valid instances of this type, but that's not > illegal, just useless. It's open to processors to issue warnings when > a type has no members, but they're not required to. > This is unfortunate because a schema author may create the above type and assume it is a valid restriction of the xs:dateTime type since validating parsers never complain only for it to fail whenever used with a [seemingly] cryptic error message. I guess it probably would be difficult to validate that the contents of the value space of the pattern facet are a subset of the contents of the value space of the original type and thus most (or all?) validating parsers just don't do it. . *sigh* -- THINGS TO DO IF I BECOME AN EVIL OVERLORD #16 I will never utter the sentence "But before I kill you, there's just one thing I want to know." _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com
|
