[xsl] Reusing and XPath expression

[Jacobus Reyneke <jacobusreyneke@xxxxxxxxx>]

Good day,

Is there some way to re-use just part of an XPath expression. Here I
made an attempt by assigning it to a variable, but the benefit of
doing it this way is very limited:

    <xsl:template match="cv:*/gl:title">
        <xsl:variable name="ancestors" select="count(ancestor::*)"/>
        <fo:block>
            <fo:inline font-size="{($title-font-size)-2*$ancestors}pt">
                <xsl:apply-templates></xsl:apply-templates>
            </fo:inline>
        </fo:block>
    </xsl:template>

In this example I resize the section titles in FO depending on the
depth of the title. Is there some way I can put the
"count(ancestor::*)" expression in one place and so re-use it in
different templates by 'calling' it? I cannot just make the expression
'global' because new values cannot be assigned to it.

This is just a question in an attempt to understand the mechanism of
re-using bits of XPath in an attempt to keep templates maintainable.

Kind regards,
Jacobus