((output
  (((f.ml (1 0) (1 13))
    (paragraph
     (((f.ml (1 0) (1 13)) (emphasis (((f.ml (1 9) (1 12)) (word foo))))))))))
 (warnings
  ( "File \"f.ml\", line 1, characters 7-7:\
   \nIdentifier in reference should not be empty.")))
