Re: [xsl] Using document() and getting back to the original doc

[Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>]

Dan,

At 01:12 PM 3/22/2004, you wrote:
> More questions related to the stylesheet parameters and using a config file.
>
> I know how to start a style sheet with a new document using the document() 
> function, but how do you get back to the document that was feed in on the 
> command line?
>
> I'm using saxon, and I pass in a configuration file on the command line 
> (so I can have different file names). This has a list of other files to 
> process and I use document() to process them. But how do I refer back to 
> the original configuration document? Is there a way to capture the input 
> file name as a parameter value - without entering it as a parameter value? 
> Is there some other way to open the "original" source document?

The XSLT engine doesn't ever have a file "open". It merely refers to node 
trees, without caring how they are built (from a file or otherwise). As you 
know, nodes can be identified using XPath; but XPath is sensitive to 
context, which leads to your problem, since your context changes when you 
do something like apply-templates select="document('myfile.xml')"

But nodes and node sets can also be bound to variables. Just as you can say

<xsl:variable name="source1" select="document('source1.xml')"/>

and thereby have a variable bound to the root node of the XPath rendition 
of the document retrieved by the function, so also can you do

<xsl:variable name="config" select="/"/>

(at the top level), which binds the root node of the "official" source tree 
(in your case, the config file) to the variable $config.

This is handly, because it allows you, in any context at all, to look at 
the $config node or any of its descendants. So you might be matching a node 
from source1.xml, and you can still say things like <xsl:value-of 
select="$config//color[@file=current()] (which gets the value of the 
'color' element descendant of the $config tree whose @file attribute is the 
same as the value of the current node).

You can also be more specific, declaring bindings like

<xsl:variable name="colors" select="//color"/>

to collect all the <color> elements in your source file and bind them to 
$colors. Like any other globally-scoped variable in XSLT, $colors will be 
the same no matter where you use it.

I hope this helps.

Cheers,
Wendell


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Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
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