fixing (just) namespaces and validation

james anderson James.Anderson at
Wed Sep 8 11:42:40 BST 1999

Simon St.Laurent wrote:
> Namespaces and validation are incompatible in cases where the namespace
> prefix changes for whatever reason, 

this claim is not universaly true. while there are dtd's for which it holds
(those with ambiguous prefixes are those with declarations with identical
prefixed names and no directly specified namespace binding.), this does not
hold for all dtd's

> For example: (Yes, I changed the colon to a dash.)
> <?xml-namespace ns="" prefix="xpdl"?>
> When it appeared in the DTD, this would tell a validating processor that
> the prefix xpdl maps to  If the
> processor then encountered elements with a namespace URI of
>, it could validate them on the basis
> of that URI and the local part even if the xpdl prefix had disappeared.

i suspect that this instruction is not necessary. it does work (to wit the
parser which is available with the cl-http server supports an instruction of
this form), but it is not necessary

in those cases where it is possible to include it in order to resolve
otherwise ambiguous names, it would also be possible to modify the prefixes so
that they are not ambiguous.

in cases where the bindings are not ambiguous (see above), it is possible to
infer the necessary bindings and resolve apparent ambiguities. the above
mentioned parser does this for directly specified namespace bindings. it would
also be possible to infer indirectly specified bindings through the respective
content models ...

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