Re: distinguish whether variable holds string or node

Play the video

Subject: Re: distinguish whether variable holds string or node set
From: David Carlisle <davidc@xxxxxxxxx>
Date: Mon, 14 Jun 2010 09:24:20 +0100

On 13/06/2010 23:03, TW wrote:

I'm not sure what you consider "safe"?

I mean, its safe to use the parameter in an xpath without having to test its type.

The most common reason for getting types wrong is a parameter that is logically always a node set but optional, people declare it as

<xsl:param name="foo"/>

but then if it is not passed in to a particular call then it defaults to an empty string so an xpath such as $foo/a/b fails with an error.

If you declare the default as

<xsl:param name="foo" select="/.."/>

This problem goes away.

If you are needing to test the types for some other reason, rather than ask how to test the types, you should ask yourself why your template is being called with the parameter set to different types. The set of types may be (unless they depend on a global stylesheet parameter) determined in advance by inspecting the stylesheet and it is always possible to arrange that each parameter is always called with a parameter of the same type. (If necessary by adding extra parameters, one for each type used.)

David


________________________________________________________________________
The Numerical Algorithms Group Ltd is a company registered in England
and Wales with company number 1249803. The registered office is:
Wilkinson House, Jordan Hill Road, Oxford OX2 8DR, United Kingdom.

This e-mail has been scanned for all viruses by Star. The service is powered by MessageLabs. ________________________________________________________________________

Current Thread

Re: distinguish whether variable holds string or node set, (continued)
- Martin Honnen - 13 Jun 2010 09:52:14 -0000
- Michael Kay - 13 Jun 2010 22:48:53 -0000

<- Previous	Index	Next ->
Re: distinguish whether varia, Michael Kay	Thread	Re: distinguish whether varia, TW
Re: distinguish whether varia, Michael Kay	Date	Re: Find the Position Index o, Philip Fearon
	Month

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

XML Editor - Download a 15 Day Free Trial Now >

See What's New in Stylus Studio >

Buy Stylus Studio - XML Editor - Now >