If user declares top-level parameter serna.stylesheet.dir, then Serna XSLT processor will set this parameter to the directory name of the top-level stylesheet. This is often necessary when some fixed set of images (e.g. icons) are used together with the stylesheet. See the example below:
<xsl:param name="serna.stylesheet.dir"/> .... <xsl:template name="show.icon"> <xsl:param name="icon.name"/> <fo:external-graphic src="{concat('url(', $serna.stylesheet.dir, '/icons/', $icon.name, '.png)')}"/> </xsl:template>
Defining the value of serna.stylesheet.dir is possible. This value will be always redefined by Serna XSLT processor, but can be used e.g. as default for other XSLT processors.