RE: Using a tree read with document() as a hash-table -- working solution

[Kay Michael <Michael dot Kay at icl dot com>]

> A quick test showed that the template-call could be avoided by using
> 
>     <value><xsl:value-of 
> select="$packtypetree//ROW[packcode=$packinfopacktype][1]/modu
> ltxt"/></value>
> 
> instead.  This is just what I needed for a hash-lookup!
> 
> On a final note - would a key() make this faster?  I still 
> have a bit of a problem understanding how it works.
> 
Yes, it would be faster, assuming that the lookup table is of some size and
is used fairly often. (In fact, it's not a hash-lookup at all unless you use
a key - it's likely to be a serial search on most processors).

Write
<xsl:key name="packcode" match="ROW" select="packcode"/>

and then replace the above code with
<value>
<xsl:for-each select="$packtypetree">
<xsl:value-of select="key('packcode',$packinfopacktype)[1]/modultxt"/>
</xsl:for-each>
</value>

The for-each is not an iteration, it's needed to establish the current
document for the key() function.

Mike Kay


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