Lx is Norman Gray's SAX-compatible reader for an sexpr-based XML syntax.

Another way of looking at this is that Lx provides a notation for XML in lisp-style sexps, similar in some ways to SXML, though that's mostly concerned with going the other way. Or, put yet another way, this is a sexp-to-SAX converter in Java.

Here's the XSLT identity transformation:

;; The XSLT identity transformation
(lx:namespace ((#f "http://www.w3.org/1999/XSL/Transform"))
  (stylesheet version: 1.0
    (template match: "node()|@*"
      (copy
        (apply-templates select: "@*|node()")))))

This is pure XSLT, and would be accepted as such by any XSL transformation engine which allows you to plug in an alternative parser.