((output
  (((f.ml (1 0) (1 7))
    (2
     (label
      ((root (f.ml (page f.ml) 00000000000000000000000000000000) f.ml)
       (label foo)))
     ()))))
 (warnings
  ( "File \"f.ml\", line 1, characters 0-6:\
   \n'{2 ...}' (section heading) should not be empty.")))
