[Xsltforms-support] applying a stylesheet in an instance to data in an instance

SourceForge Headquarters 225 Broadway Suite 1600 San Diego, CA 92101 +1 (858) 422-6466

In a form I'm working on, I'd like to apply a stylesheet located in a
document instance (instance('filter') to an input document located in
another instance (instance('userdoc')).

It doesn't seem to be working, and I wonder if anyone here can see
what I'm doing wrong.

I've studied the code for the existing transform() function, which accepts
a node set and a URI and then calls XsltForms_browser.transformText
with that same node set, that same URI, and a flag to signal that the
second argument is a URI and not a literal string containing an angle-bracket
encoding of a stylesheet.  

If I understand the code for the underlying transformText function
correctly (not guaranteed!), it can accept either a URI or a stylesheet
in string form in its second argument, and its third argument tells the
system which case applies.  
  - If the third argument is true, the second argument is passed to
    a parser and a DOM object is returned.
  - If the third argument is false, the second argument is used to
    load an external document, and the resulting DOM is returned.
(At least, I assume the results are DOM objects.)

Other calls to transformText() seem to use strings successfully in
the second argument.

So I wrote an extension function that looks like this:

      function bmt_applyxslt_ns_s(nsXML, sXSLT) {
         if (arguments.length !== 2) {
            throw XsltForms_xpathFunctionExceptions.transformInvalidArgumentsNumber;
         }
	 return nsXML.length === 0? "" : XsltForms_browser.transformText(XsltForms_browser.saveXML(nsXML[0]), sXSLT, true);
      }

This is almost verbatim the same as the source code for transform(),
except for the argument names and 'true' instead of 'false' in the
third argument.  (I notice now that I ought to change the name of
the exception, perhaps, too.)

I register the function with XSLTforms in the usual way.

  <xf:setvalue 
      ref="instance('userout')/self::data" 
      value="bmt:s_applyxslt_ns_s(instance('userdoc'), serialize(instance('filter')))"/>

The form loads as expected and the function seems to be called
without incident and without error messages (and alert messages 
confirm that the arguments look pretty much as I expect them to look).  
But the result is consistently not the output I expect from the stylesheet, 
but a document which reads in its entirety:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml">
<head><title></title></head>
<body>
<pre></pre>
</body>
</html>

Anyone have a clue?  Anyone have a better (or just different) way to go about
this?

Thanks!

Michael Sperberg-McQueen

-- 
****************************************************************
* C. M. Sperberg-McQueen, Black Mesa Technologies LLC
* http://www.blackmesatech.com 
* http://cmsmcq.com/mib                 
* http://balisage.net
****************************************************************