Re: Be careful writing XPath expressions when the XML couldhav

From: Ihe Onwuka <ihe.onwuka@gmail.com>
To: "Costello, Roger L." <costello@mitre.org>
Date: Tue, 29 Jul 2014 10:58:55 +0100

Play the video

Did not read the article but stating the obvious from a strictly pattern matching XSLT perspective if there is no element then there is no pattern to match.

If you like to save your brain from the burden of all the edge cases - don't go there.

On Tue, Jul 29, 2014 at 10:43 AM, Costello, Roger L. <costello@mitre.org> wrote:

Hi Folks,

Are you writing XPath expressions?

XPath is embedded in a lot of things: XQuery, Schematron, XSLT, XML Schema. If you are using XML, there is a good chance you are writing XPath expressions.

Heads up!

Failure to take into account the following rule will result in countless headaches and hard-to-detect bugs.

Rule: The result of evaluating an XPath expression
that compares a non-existent element against
anything is always false.

More ... http://xfront.com/Be-Careful-Writing-XPath-Expressions-Against-XML-Documents-that-may-have-Non-Existent-Elements.pdf

/Roger

_______________________________________________________________________

XML-DEV is a publicly archived, unmoderated list hosted by OASIS
to support XML implementation and development. To minimize
spam in the archives, you must subscribe before posting.

[Un]Subscribe/change address: http://www.oasis-open.org/mlmanage/
Or unsubscribe: xml-dev-unsubscribe@lists.xml.org
subscribe: xml-dev-subscribe@lists.xml.org
List archive: http://lists.xml.org/archives/xml-dev/
List Guidelines: http://www.oasis-open.org/maillists/guidelines.php

References:
- Be careful writing XPath expressions when the XML could havenon-existent elements
  - From: "Costello, Roger L." <costello@mitre.org>

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index]

PURCHASE STYLUS STUDIO ONLINE TODAY!

Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!

Download The World's Best XML IDE!

Accelerate XML development with our award-winning XML IDE - Download a free trial today!

Subscribe in XML format

RSS 2.0
Atom 0.3

Stylus Studio has published XML-DEV in RSS and ATOM formats, enabling users to easily subcribe to the list from their preferred news reader application.

Stylus Studio Sponsored Links are added links designed to provide related and additional information to the visitors of this website. they were not included by the author in the initial post. To view the content without the Sponsor Links please click here.

XML Editor - Download a 15 Day Free Trial Now >

See What's New in Stylus Studio >

Buy Stylus Studio - XML Editor - Now >