Bug 4868 – [XPath] abbreviations for / and // syntactically incorrect

Bug 4868 - [XPath] abbreviations for / and // syntactically incorrect

Summary:

[XPath] abbreviations for / and // syntactically incorrect

Status:	RESOLVED FIXED

Product:	XPath / XQuery / XSLT
Component:	XPath 2.0
Version:	Recommendation
Platform:	PC Windows XP

Importance:	P4 normal
Target Milestone:	---
Assigned To:	Don Chamberlin
QA Contact:	Mailing list for public feedback on specs from XSL and XML Query WGs

URL:
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Keywords:

Depends on:
Blocks:
	Show dependency tree / graph

Reported:	2007-07-19 07:03 UTC by Ryan Gustafson
Modified:	2007-11-16 11:58 UTC (History)
CC List:	0 users (show)

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Description Ryan Gustafson 2007-07-19 07:03:26 UTC

In the version found at http://www.w3.org/TR/xpath20/#id-path-expressions

The statements which indicate to sometimes abbreviate / as
fn:root(self::node()) treat as document-node()/ and // as fn:root(self::node())
treat as document-node()/descendant-or-self::node() are not syntactically
correct.

My own parser, as well as the parser at
http://www.w3.org/2006/11/applets/xpathApplet.html refuse to parse such input.

The Formal Semantics http://www.w3.org/TR/xquery-semantics/#id-path-expressions
indicate a parenthesized version of the same construct.

Are the Formal Semantics are correct and XPath needs to be corrected?

Comment 1 Michael Kay 2007-07-19 08:49:59 UTC

Personal response: Yes, I think you're right.

fn:root(self::node()) treat as document-node()/X

does not parse because the expression on the lhs of "/" must be a StepExpr, and
a TreatExpr is not a StepExpr. It needs to be parenthesized.

Comment 2 Don Chamberlin 2007-07-31 17:40:35 UTC

On July 31, 2007, the Query and XSLT working groups agreed to add parentheses
to the expansions of leading-/ and leading-// in path expressions, as suggested
by this bug report. The revised expansions will appear in a future errata
document.
Regards,
Don Chamberlin (for the joint working groups)

Comment 3 Michael Kay 2007-11-16 11:58:04 UTC

The agreed change will be published in Erratum XP.E3 for XPath, XQ.E3 for
XQuery.