Re: Well-formed and valid
"Frank Boumphrey" <bckman@i...> writes: > > james anderson <James.Anderson@m...> writes: > > > > > > ... it is possible to have a document that is well-formed but > > > > not valid XML 1.0, but still conforms to Namespaces, RDF, or XLink > > > > (though not XHTML, which requires validity for strict conformance). > > Well XHTML is no different from any other _document type_. A document type > such as docbook or XHTML must conform to a DTD or it would not be a document > type! Wrong. A document type needs to conform to the specification that defines it: the specification may or may not include a DTD, and may or may not require the DTD to be used, but the DTD is at best an optional (if extremely useful) part of a document type specification. Here's an example of a document type whose specification does not include a DTD: Memo Document Type ------------------ Every memo document consists of a root element named "memo" with two element children: "number" and "body", optionally separated by whitespace. The contents of the "number" element shall be a number between 1 and 99,999, assigned sequentially; the contents of the "body" element shall be text containing a minimum of one and a maximum of three sentences, using UK orthography. Here's a document conforming to that document type: <?xml version="1.0"?> <memo> <number>2,126</number> <body>Look, mum, no DTD!</body> </memo> Now, I could have written a DTD and required its use as *part* of the document type specification: <!ELEMENT memo (number, body)> <!ELEMENT number (#PCDATA)> <!ELEMENT body (#PCDATA)> However, it would be trivially easy to write documents that conform to the DTD but not to the document type: <?xml version="1.0"?> <!DOCTYPE memo SYSTEM "memo.dtd"> <memo> <number>Let me not to the marriage of true minds</number> <body>123</body> </memo> All the best, David -- David Megginson david@m... http://www.megginson.com/ 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/ and on CD-ROM/ISBN 981-02-3594-1 To unsubscribe, mailto:majordomo@i... the following message; unsubscribe 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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