Re: [xsl] [xsl-list] Storing an XPath fragment in a variable

[Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>]

Hi Jason,

At 04:18 PM 7/13/2005, you wrote:
> I'm using the following partial XPath expression...:
>
> [name()='RED' or name() = 'GREEN' or name() = 'BLUE']
>
> ... in several locations in my stylesheet:
>
> <xsl:for-each select="/*/*[1]/*[name()='RED' or name() = 'GREEN' or
> name() = 'BLUE']">
>
> <xsl:for-each select="*[name()='RED' or name() = 'GREEN' or name() = 'BLUE']">

This works, but it's exactly the same as select="RED | GREEN | BLUE", so 
why don't you use that?

*[name()='RED' or name() = 'GREEN' or name() = 'BLUE'] translates as "all 
child elements whose name is 'RED', or 'GREEN', or 'BLUE'"

RED | GREEN | BLUE translates as "all RED, GREEN or BLUE child elements".

> Is it possible to store a fragment of an XPath expression in a
> variable or is there another method of eliminating redundancy that I'm
> not aware of?

No there isn't, without an evaluation function such as saxon:evaluate that 
lets you parse and evaluate strings back into as XPath.

On the other hand, this isn't really necessary most of the time, since you 
can easily bind the set of nodes (whatever RED, GREEN and BLUE child 
elements you have) to a variable, and reuse that.

So

<xsl:variable name="brights" select="RED | GREEN | BLUE"/>
 ...
<xsl:apply-templates select="$brights"/>

works just fine. So will select="$brights | GREY" if you want to add GREY 
children to the mix.

Whether you need something more powerful than this we can't see without 
looking at your actual case; but this is usually plenty powerful enough.

Cheers,
Wendell


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Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
Mulberry Technologies, Inc.                http://www.mulberrytech.com
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Suite 207                                          Phone: 301/315-9631
Rockville, MD  20850                                 Fax: 301/315-8285
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