Re: A Counter Variable in XSLT?

Grant,

Without seeing more of your problem context, I can't say for sure, but you
might consider some options before resorting to mutable variables.

1. Will <xsl:number> suffice?  See http://www.w3.org/TR/xslt#number.

2. If <xsl:number> won't do, and you are counting nodes, or any
characteristics that can be determined about nodes, you might be able to use
the count() function on a suitable node-set (specified with an appropriate
XPath expression).  Or in some contexts you can use the position() function.

3. If neither of options 1 or 2 is suitable, you can probably count what you
want by using a recursive named template.  I won't give an example here,
since I don't know if it is appropriate for your problem.  But this is about
the only way you can do something like: $matchNumber = $matchNumber + 1
(without using extensions).

I can answer the first part of your question: no, variable bindings in XSLT
are scoped to the following siblings (and their descendants) of the element
in which they are "declared" with <xsl:variable>.  Once declared, the values
cannot be changed.  You could have identically named variables in every
template in your stylesheet if you wanted, and they would all be distinct.
You can have top-level bindings that are visible everywhere, but the values
can't be changed anywhere else.

The particulars are presented succinctly, but completely, at
http://www.w3.org/TR/xslt#variables.

As for extensions that allow mutable variable bindings, I'm sure others on
the list can speak about that.  I've never encountered a transformation
problem that required it, though.

Hope this helps.

Paul Tyson, Principal Consultant                   Precision Documents
paul@xxxxxxxxxxxxxxxxxxxxxx              http://precisiondocuments.com
     "The art and science of document engineering."


----- Original Message -----
From: "Grant Mc Auley" <gmcauley@xxxxxxxxxxx>
To: "Xsl-List@Lists. Mulberrytech. Com" <xsl-list@xxxxxxxxxxxxxxxxxxxxxx>
Sent: Thursday, October 04, 2001 5:55 PM
Subject:  A Counter Variable in XSLT?


> Greetings,
>
> I want to create a "counter variable" - one that I can increment
> within a stylesheet.  Something like:
>
>   <xsl:variable name="matchNumber" select="'0'"/>
>
> (and later...)
>
>   <xsl:value-of select="$matchNumber++"/>
>
> I know $matchNumber++ won't work, but is there anyway to do this
> in XSLT, or do I have to use an extension?  (I am currently using
> Xalan)
>
> Thank you,
>
> Grant Mc Auley
>
>
>  XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list
>


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