[xsl] Pattern: Replicating Key Table Construction for Debugging

["W. Eliot Kimber" <eliot at isogen dot com>]

This should have been obvious, but it took me a while to figure it out
and I know a lot of people are struggling with key-based processing:

There's no direct way to see what the entries in a table are (e.g., the
equivalent of Hastable.getKeySet() in Java). However, you can easily
replicate what the key table is doing and sanity check what's happening.
All you do is a for-each from the root that uses the same select rule as
the key.

For example, if your key declaration is:

<xsl:key name="primary" 
  match="index.marker" 
  use="normalize-space(concat(primary/@sortas,
primary[not(@sortas)]))"/>

Then to see what is actually going into the table, just do this:

<xsl:for-each select="//index.marker">
 <xsl:message>key='<xsl:value-of 
  select="normalize-space(concat(primary/@sortas, 
                                
primary[not(@sortas)]))"/>'</xsl:message>
</xsl:for-each>

This should print out the equivalent of all the entries in the table.
You can also capture the key value and do a lookup in the table to see,
for example, how many of that entry are in the table under that key.

<xsl:for-each select="//index.marker">
 <xsl:variable name="tempkey">
  <xsl:value-of
    select="normalize-space(concat(primary/@sortas, 
                                 primary[not(@sortas)]))"/>
 <xsl:variable>
 <xsl:message>key='<xsl:value-of select="$tempkey"/>'</xsl:message>
 <xsl:message>  <xsl:value-of select="count(key('primary', $tempkey))/>
items found
  </xsl:message>
</xsl:for-each>  

Cheers,

Eliot
-- 
W. Eliot Kimber, eliot@isogen.com
Consultant, ISOGEN International

1016 La Posada Dr., Suite 240
Austin, TX  78752 Phone: 512.656.4139

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