(define (namespaced-tag? tag)
  (let ((name (symbol->string tag)))
    (substring-index ":" name)))

(define (strip-namespace tag)
  (let ((name (symbol->string tag)))
    (string->symbol (last (string-split name ":")))))

(define (strip-namespaces xml)
  (pre-post-order*
   xml
   `((*text* . ,(lambda (_ str) str))
     (*default* . ,(lambda (tag elements)
                     (if (namespaced-tag? tag)
                         (cons (strip-namespace tag) elements)
                         (cons tag elements)))))))