[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] RE: Can we treat XML elements and attributes as sets
Thanks Mike for your comments.. Regards, Mukul --- Michael Kay <mike@s...> wrote: > The terminology of each of the specs is slightly > different. > > XML doesn't know about namespaces at all > (unfortunately). > > The XML namespaces spec says "If the URI reference > in a default namespace > declaration is empty, then unprefixed elements in > the scope of the > declaration are not considered to be in any > namespace. " > > The Infoset says, of the [namespace name] property > of an element information > item: " If the element does not belong to a > namespace, this property has no > value." > > The XPath 2.0 data model says that the name of an > element or attribute is a > QName as defined by the xs:QName data type in XML > Schema. XML Schema Part 2 > says that a QName contains a namespace name and a > local part; oddly, it does > not mention that the namespace name might be absent > or null. > > Most of these specs avoid using the dreaded "null" > word, probably because of > its traumatic history in relational databases. But > XSLT says (in 3.1): > > "Throughout this specification, an element or > attribute that is in no > namespace, or an expanded-QName whose namespace part > is an empty sequence, > is referred to as having a null namespace URI." > > This is to enable the spec to retain terminology > that's familar from XSLT > 1.0. > > Note that a namespace URI cannot itself be null; but > a property of an object > that might otherwise hold a namespace URI, and that > might be referred to as > "the namespace URI property", can be said to be null > when the namespace URI > is absent. > > Michael Kay > http://www.saxonica.com/ ____________________________________________________ Start your day with Yahoo! - make it your home page http://www.yahoo.com/r/hs
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