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[XSLT2] debugging XSLT apps; getting information about items and sequences

From: Tobias Reif <tobiasreif@pinkjuice.com>
Date: Wed, 11 Jun 2003 17:27:09 +0200
Message-ID: <3EE74A4D.9060807@pinkjuice.com>
To: public-qt-comments@w3.org

Hi

While working on XSLT apps, I need to inspect some variables and parameters.

I need to get the type information and the positions in the sequence 
printed out (and possibly more info), not just the string value.

I currently use

   <xsl:message>
     <xsl:copy-of select="trace($parent,'parent')"/>
     <xsl:copy-of select="trace($children,'children')"/>
   </xsl:message>

(sometimes wrapped inside <xsl:if test="$debug"/>)

=> prints

parent [1]: xs:string: span
children [1]: xs:string: div
children [2]: xs:string: p
children [3]: xs:string: span
children [4]: xs:string: span
spandivpspanspan

The above is useful, but in addition to what I want, I get the string 
value of the sequences (last line). The latter is not really useful in 
my case, and not needed.

This

   <xsl:message>
     <xsl:copy-of select="$parent"/>
     <xsl:copy-of select="$children"/>
   </xsl:message>

=> prints

span
spandivpspanspan

The above is way less informative, and not useful in my (and probably 
other) scenario(s).

I guess I'd like to have something like this:

   <xsl:message>
     <xsl:inspect select="$parent"/>
     <xsl:inspect select="$children"/>
   </xsl:message>

=> would print

parent [1]: xs:string: span
children [1]: xs:string: div
children [2]: xs:string: p
children [3]: xs:string: span
children [4]: xs:string: span

xsl:inspect would simply return a string, and would not print anything 
by itself. This string can be stored in a variable, processed further, 
written to a run log, or simply printed out as in the above example.

Some of my requirements:

1. I want to get information about a certain sequence at a certain 
point, which may not be the same point where I use it.

2. I need the information provided by trace(), but I want to decide on 
my own if I print this string or not. The function (eg a version of 
trace()) or element I want should not print anything, but only return a 
string.

3. I only want to see those values when I debug the XSLT.
So I need to be able to enclose everything that prints out debug 
messages in <xsl:if test="$debug"/>

4. It should work in all conforming processors. I want a solution, not a 
workaround :)

Tobi

[the examples are run with Saxon 7.5.1]

-- 
http://www.pinkjuice.com/
Received on Wednesday, 11 June 2003 11:27:25 GMT

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