RE: [xsl] parameters in XSLT 2.0

["Michael Kay" <mike@xxxxxxxxxxxx>]

> For example, first I have this variable to suck in outside data:
> 
>    <xsl:variable name="raw-biblist">
>      <modsCollection xmlns="http://www.loc.gov/mods/v3";
>        xmlns:bib="http://purl.org/NET/xbiblio/citeproc";>
>        <xsl:copy-of select="$bibrecord/*/mods:mods"/>
>      </modsCollection>
>    </xsl:variable>

It's certainly not obvious that copying the source data in this way is
achieving anything useful.
> 
> Then I have this variable, which creates the enhanced data 
> you mention above:
> 
>    <xsl:variable name="enhanced-biblist">
>      <mods:modsCollection 
> xmlns:bib="http://purl.org/NET/xbiblio/citeproc";>
>        <xsl:choose>
>          <xsl:when test="$sort_order-bib='citekey'">
>            <xsl:apply-templates 
> select="$raw-biblist/mods:modsCollection" mode="sort_citekey"/>
>          </xsl:when>
>          <xsl:when test="$sort_order-bib='cited'">
>            <xsl:apply-templates 
> select="$raw-biblist/mods:modsCollection" mode="sort_cited"/>
>          </xsl:when>
>          <xsl:when test="$sort_order-bib='author-year'">
>            <xsl:apply-templates 
> select="$raw-biblist/mods:modsCollection" mode="sort_author-year"/>
>          </xsl:when>
>        </xsl:choose>
>      </mods:modsCollection>
>    </xsl:variable>
> 
> ... and then I do:
> 
>    <xsl:variable name="bib:formatted-biblist">
>      <xsl:apply-templates 
> select="$enhanced-biblist/mods:modsCollection/mods:mods"
>        mode="temp-placeholder"/>
>    </xsl:variable>
> 
> The thinking that prompted my question is that maybe the 
> enhanced data 
> gathered in the sort* modes in the second variable could be condensed 
> down to a few (tunnel) parameters, rather than the 8 or so nodes I 
> create in the temporary tree. 

Possibly: I can't see what the apply-templates calls are doing, so it's hard
to tell. If the apply-templates calls are creating new elements, then
there's probably no extra cost (in fact it may be cheaper) to wrap these
elements in a document node (a temporary tree). If there's a saving to be
made, then it will be made by avoiding creating new nodes (or copying
existing nodes).

Two things are worth remembering about performance engineering:

(a) don't tune your code unless it is failing to meet its performance
requirements.

(b) the only way to know whether your tuning attempts are worthwhile is to
make measurements before and after.

Michael Kay
http://www.saxonica.com/