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Bug 4872 - SML shouldn't reference xpointer
Summary: SML shouldn't reference xpointer
Status: RESOLVED DUPLICATE of bug 4636
Alias: None
Product: SML
Classification: Unclassified
Component: Core (show other bugs)
Version: unspecified
Hardware: PC Windows XP
: P2 normal
Target Milestone: ---
Assignee: C. M. Sperberg-McQueen
QA Contact: SML Working Group discussion list
URL:
Whiteboard:
Keywords: resolved
Depends on:
Blocks:
 
Reported: 2007-07-19 21:52 UTC by Paul Grosso
Modified: 2007-10-16 23:35 UTC (History)
0 users

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Description Paul Grosso 2007-07-19 21:52:34 UTC
The XML Core WG just noticed that the latest (editor's)
draft of SML 1.1 at
http://dev.w3.org/cvsweb/~checkout~/2007/xml/sml/build/sml.html?content-type=text/html;%20charset=utf-8
has a normative reference to "XPointer xpointer() Scheme"
http://www.w3.org/TR/xptr-xpointer/

It should be noted that this is a (non-last call)
Working Draft from 2002 on which no work is planned.
In fact, the xpointer() scheme failed CR, and was
withdrawn as a W3C work item.

You should not plan to reference the xpointer() scheme
in your specification.

paul

Paul Grosso for the XML Core WG
Comment 1 C. M. Sperberg-McQueen 2007-07-19 22:11:15 UTC
I had been meaning to propose that instead of the xpointer
scheme, the SML spec use the xpath1 scheme.  I hadn't gotten
around to it, but this seems an opportune place and time.

As far as I can tell, there is no particular bit of
functionality present in xpointer that is not present in
xpath1, that SML depends upon. Indeed, at least some examples
of the extra functionality (like being able to point at
ranges that do not contain well-balanced XML) would probably
be problematic for most SML implementations.  So xpath1
is probably a better fit in any case.

Of course, xpath2 should also be considered.
Comment 2 Pratul Dublish 2007-09-27 01:16:15 UTC
xpath1 and xpath2 schemes are not W3C recommendations. The element() scheme is a W3C recommendation but it is difficult to use and fragile since it uses numeric child sequences. E.g., 

element(/1/2)

However, it is expressive enough to represent SML references since they always point to a unique element in a doc
Comment 3 C. M. Sperberg-McQueen 2007-09-27 02:44:43 UTC
I'm not quite sure what you mean.  XPath 1.0 and XPath 2.0 
are both W3C recommendations.

It's true that no W3C Rec specifies their use as an XPointer
scheme.  But the problem which gave rise to this bug report
is that the expression language of the xpointer() scheme is 
defined only by a Working Draft (and one on which no WG is
now working); on that point, XPath 1.0 and XPath 2.0 are on
a rather different footing.

The element() scheme seems far too brittle to be useful for 
cross references in a dynamic system.  Relying on it 
would make SML reference error prone, and at the same time
ensure that most of the errors would not be readily detectable
(because the reference will not fail to resolve, just resolve
to the wrong element).
Comment 4 Pratul Dublish 2007-09-27 15:52:30 UTC
Although the xpath1 and xpath2 XPointer schemes are registered in the XPointer Registry ( http://www.w3.org/2005/04/xpointer-schemes/), they are not W3C recommendation (see see Paul Grosso's email http://lists.w3.org/Archives/Public/public-sml/2007Jul/0093.html)

Sure XPath 1.0 and XPath 2.0 are W3C recommendation, but these should not be confused with the xpath1 and xpath2 XPointer schemes. The XPointer registry does not have a spec for the xpath2 scheme, and the spec for the xpath1 scheme (http://www.tei-c.org/P5/Guidelines/SA.html#SATSXP) is not a W3C recommendation
Comment 5 Virginia Smith 2007-10-16 23:35:58 UTC

*** This bug has been marked as a duplicate of bug 4636 ***