Subject: Re: [xsl] XML Schema/XSL conflict (can't differentiate unqualified locals)? From: David Carlisle <davidc@xxxxxxxxx> Date: Tue, 9 Oct 2001 11:29:16 +0100 |
I think namespaces are intrinsically very confusing. (1) people don't understand that there is no "resource" that the URI identifies Of course this is made rather worse by the schema WG's decision to make the namespace URI effectively the default location of the schema. (2) people don't understand why the rules are different for elements and attributes Rules is rules. (3) people don't understand whether or not prefixes are supposed to be significant Of xourse XPath (and its followers) makes this more subtle than a reading of the namespace spec would make appear. The namespace spec really implies that it would be trivial to namespace normalise a namespace conformant document to change prefixes etc. But using prefixes in attribute values (and possibly, but not in XSLT) element content makes this a lot trickier. (4) people don't understand the arbitrariness of some of the rules, e.g. that the default namespace can go out of scope for descendants but an explicit namespace can't You can't unmap a prefix once bound, whereas you can unbind the null prefix, but is this really very confusing, do people often need to locally unbind the default namespace anyway>? (I'd say almost never except for the rather bizarre use of unqualified local elements in schema) (5) people don't understand the difference between namespace nodes and namespace declarations True. (6) people don't understand the difference between namespace declarations and attributes True. In my view, namespaces are a disastrously bad piece of design, almost as bad as DTDs. All these confusions derive directly from the decision to add a fundamental architectural feature to XML as a "bolt-on extra", which is almost always bad software engineering. On the other hand it was politically very important in the beginning to have SGML compatibility, and perhaps a architectually cleaner solution would just have failed in the marketplace (but who knows:-) David _____________________________________________________________________ This message has been checked for all known viruses by Star Internet delivered through the MessageLabs Virus Scanning Service. For further information visit http://www.star.net.uk/stats.asp or alternatively call Star Internet for details on the Virus Scanning Service. XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list
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