Re: [xsl] Omnimark vs. XSL (Saxon) Challenge

[Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>]

At 05:00 AM 3/17/2004, Michael Müller-Hillebrand wrote:
> I use this set of nodes just for the sake of looping a certain number of 
> times. In Jeni Tennison's book "XSLT and XPath On The Edge" it is called 
> "The Piez Method". You are right, I don't need two variables (just an old 
> habit...).

Will I ever live it down? But yes ... and Mike knows the provenance of the 
technique. :->

Jeni called it that because she was tickled (she said) by how 
counter-intuitively obvious it was as a way of avoiding more cumbersome 
methods, and wanted to give me credit for its small measure of tricky (if 
not diabolical) inventiveness (my words not hers: her word might have been 
"sweet"). But everyone who uses it (including me, when I do) should really 
be ashamed of themselves. At best, it's a shortcut and should be avoided 
except in very constrained circumstances. Such as: you don't need to 
iterate many times in any case, and a node set guaranteed to be large 
enough is readily available. One rule of thumb: if you need to go parse 
something to get enough nodes, it's not worth it. Another: don't ever look 
at set X and suppose that you need to iterate count(X) times -- just 
iterate over the set X that you would have counted. That is, it's silly to 
do this:

<xsl:for-each select="$bignodeset[position() &lt;= count($nodeset)">
  ...
</xsl:for-each>

when you could simply do

<xsl:for-each select="$nodeset">
  ...
</xsl:for-each>

Believe it or not, I've seen it done the hard way.

All in all, I can think of other ways I'd rather go down in history. If 
only I'd first figured out positional grouping using keys!

Cheers,
Wendell



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Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
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