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> -----Original Message----- > From: John Cowan [SMTP:cowan@l...] > > Let's say that you have an element with #PCDATA content that's > supposed to contain a date, like this: > > <CREATED>1999-01-21</CREATED> > > You can say that this is a date in a standard way by adding the > following to the DTD: > > <!NOTATION ISO-8601-date SYSTEM "http://www.iso.ch/8601"> > <!ATTLIST CREATED > type NOTATION(ISO-8601-date) #FIXED "ISO-8601-date"> > > which says that all CREATED elements have an attribute named "type", > of type NOTATION, with fixed value "ISO-8601-date", which is a > notation bound to the ISO 8601 definition of a date. This notation > is verbose because there's flexibility in it which I'm not really > exercising, to have elements whose content can be one of multiple > datatypes, like: > > <!NOTATION int32 SYSTEM "..."> > <!NOTATION int64 SYSTEM "...."> > <!NOTATION float SYSTEM "......"> > <!ATTLIST MUTABLE > type NOTATION(int32,int64,float) #REQUIRED> > > which declares that MUTABLE elements must have a "type" attribute > whose value is either "int32" or "int64" or "float", and the notation > declarations tell you what those mean. The systemids are > URLs that point to the definition of the datatype (in English or > whatever language natural or formalized). > Unfortunately that information is only really useful for document authors (which is fine, in itself) - it doesn't appear (to me) to be any use to parsers. It can be of /some/ use to custom parser code, but only when that code has prior knowledge of these notation definitions. And that's a shame. Perhaps we need some standard notations? Matt. xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ To (un)subscribe, mailto:majordomo@i... the following message; (un)subscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
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