I have an XSL program which in turn generates an XSL program, which depending on the input might look like this:
<xsl:variable name="patterns"/> <!--empty in this particular case-->
<xsl:template name="token">
<xsl:for-each select="$patterns/pattern">
...
When I then run the generated stylesheet, Saxon, bless its heart, is apparently doing some kind of static analysis and complains:
XPTY0019: Required item type of first operand of '/' is node(); supplied value has item type xs:string
and won’t even compile the stylesheet.
My workaround was to generate a dummy element in the $patterns nodeset, but is there any cleaner approach here, or way to suppress the compile error?
According to http://www.w3.org/TR/xslt20/#variable-values, “If the variable-binding element has empty content and has neither a select attribute nor an as attribute, then the supplied value of the variable is a zero-length string.”.
So you need to change that, for instance by doing
<xsl:variable name="patterns" select="()"/>to bind an empty sequence as the variable value.