Have you tried using an attribute value template (7.6.2) as follows?
<ext:field select="{...}" .../>
The curly braces are commonly used to evaluate XPath within attributes of
literal result elements such as:
<img src="{...}"/>
Note that the expression is converted to string, just as with <xsl:value-of/>.
If you want to use node sets or if you
need to evaluate the expression in a custom context, then using attribute
value template may not work.
-- Frank Weiss
Simon Kitching wrote:
> Hi All,I am trying to implement an extension element like this: <ext:field
> select="..." myattr1="..."
> myattr2="..."/>where the select should be able to contain anything that would
> normally be validin an <xsl:value-of
> select="..."/> expression. I have got this mostly working, but my code fails
> for this type of thing:<xsl:variable
> name="foo" select="'some value'"/><ext:field select="$foo"/>My code which
> evaluates the specified select statement
> reports that the variable "foo" cannot be found, though XPath expressions are
> evaluated correctly(as far as I can
> see). Variable "foo" is definitely in scope; replacing a call to myextension
> with code like <xsl:value-of
> select="$foo"/> works fine.Within my extension element method, I use the
> following code (mostly grabbedfrom the
> PipeDocument code):XPathContext xpContext =
> procContext.getTransformer().getXPathContext();XPath dynamicXPath = new
> XPath( selectStr, xpContext.getSAXLocator(),
> xpContext.getNamespaceContext(), XPath.SELECT,
> procContext.getTransformer().getErrorListener());XObject xobj =
> dynamicXPath.execute( xpContext,
> procContext.getContextNode(), // I suspect this is the problem
> xpContext.getNamespaceContext());Note that global
> variables can be accessed from the select expression, just not variables
> declared in the same template as the
> extension element invocation.My suspicion (which may be wildly wrong) is that
> the node returned by
> procContext.getContextNode()is the template node, not the <ext:field> node.
> And of course any variables declaredwithin
> that node are therefore not in scope.Does anyone have any suggestions how to
> deal with this?I cannot find any methods
> that would return the <ext:field> node itself, and am not surethat if I did
> find one then xpath expressions might not
> be right if I used it. Note also thatthe select expression might be *any*
> valid expression.On a related question, I am
> somewhat confused about what node getContextNode()is returning anyway :-)I am
> assuming the following:* a DOM (or
> DOM-equivalent) has been built for the source xml document* a DTM tree of
> "wrapper" nodes is built; each node has a
> reference back to the underlying source document node. It is to this DTM
> tree that any XSL variables are
> attached.* the getContextNode() method returns a reference to the DTM node
> which wraps the currently matched source
> document node.Could someone kindly correct me if I am off-beam here? Or maybe
> refer me toan appropriate architectural
> document?Many thanks in advance,Simon
