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Re: New draft, 13 Nov 2007

From: Norman Walsh <ndw@nwalsh.com>
Date: Tue, 13 Nov 2007 12:29:01 -0500
To: public-xml-processing-model-wg@w3.org
Message-ID: <m21wauvyua.fsf@nwalsh.com>
/ Rui Lopes <rlopes@di.fc.ul.pt> was heard to say:
| Norman Walsh wrote:
|>   * Attempt to support both XPath 1.0 and XPath 2.0; there's more to
|>     be done, but see Section 2.8, “XPaths in XProc”.
| On a quick read of this part of the spec, I've come across the following:
| "An XProc implementation can use either [XPath 1.0] or [XPath 2.0] to
| evaluate these expressions. [...]"
| Which means that, within a pipeline, each expression may be evaluated
| against different XPath engines (read: versions). Correct?

Yes, as spec'd, different expressions may be evaluated by different
engines. (Though any given expression will only be evaluated by a
single engine.)

| If so, when I read on the spec the following system property:
| "p:xpath-version
| Returns the version of XPath implemented by the processor for
| evaluating XPath expressions on XProc elements."
| Which value(s) should an XProc implementation return, if it provides
| two XPath engines? "1.0", "2.0", "1.0 2.0" ?

Yeah, I thought about this but decided we didn't need to go that far.
But maybe we do.

| Nevertheless, I would prefer to have the p:xpath-version available
| only at top-level elements (p:pipeline and p:pipeline-library). IMHO,
| this whould reduce the confusion of users when looking at a pipeline
| and read several XPath expressions written in different versions - on
| the same document. Isn't just top-level enough?

Maybe. I'd be happy if everyone agreed that it was only necessary at
the top level.

                                        Be seeing you,

Norman Walsh <ndw@nwalsh.com> | Men are more like the times they live
http://nwalsh.com/            | in than they are like their
                              | fathers.--Ali Ibn-abi-talib

Received on Tuesday, 13 November 2007 17:29:12 UTC

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