Re: [PATCHES] xml2 contrib patch supporting default XML namespaces

On 3/6/07, Nikolay Samokhvalov <samokhvalov@gmail.com> wrote:
> On 3/6/07, Mike Rylander <mrylander@gmail.com> wrote:
> > Attatched you'll find a patch that I've been kicking around for a
> > while that I'd like to propose for inclusion in 8.3.  I attempted to
> > submit this through the original xml2 author (as far back as the  7.4
> > days) but got no response.
> >
> > It's really fairly trivial, but I will be using the features it
> > provides in production soon, so I'd like to see it applied against the
> > contrib xml2 module.  The patch adds support for default XML
> > namespaces in xml2 by providing a mechanism for supplying a prefix to
> > a named namespace URI.  It then wraps the namespace-capable functions
> > in backward-compatible equivalents so that old code will not break.
>
> 1) And what about non-default namespaces?

I'm not sure I understand.  If the namespace already has a prefix then
it works fine.  This patch simply gives a known non-prefixed namespace
URI a prefix so one can write XPath that looks like

  //marc:datafield[@tag='245']/marc:subfied[@code='a']

instead of

  //*[local-name()='datafield' and
@tag='245']/*[local-name()='subfied' and @code='a']

A little two node example is painful enough, now imagine a non-trivial
example with backtracking conditionals... :P

> 2) What if my XPath query has different prefix, that also should be
> mapped to the same URI? (Not frequent case, but this really can occur
> -- e.g. XML doc has prefix 'local' for URI='http://127.0.0.1', but
> XPath should have 'loc' for the same URI.)
>

Both prefixes work fine as multiple prefixes can map to the same URI.

> --
> Best regards,
> Nikolay
>


--
Mike Rylander
mrylander@gmail.com
GPLS -- PINES Development
Database Developer
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