Evaluate a template string value, i.e. the parent list is interpreter
as template content and the resulting tree string value is returned
This is needed for example by xsl:comment and xsl:processing-instruction
ctxt :
the XSLT transformation context
node :
the stylesheet node
parent :
the content parent
Returns :
the computed string value or NULL, must be deallocated by the
caller.
Evaluate a attribute value template, i.e. the attribute value can
contain expressions contained in curly braces ({}) and those are
substituted by they computed value.
ctxt :
the XSLT transformation context
node :
the stylesheet node
name :
the attribute QName
ns :
the attribute namespace URI
Returns :
the computed string value or NULL, must be deallocated by the
caller.