((output
  (((f.ml (1 0) (1 7))
    (3
     (label
      ((root (f.ml (page f.ml) 00000000000000000000000000000000) f.ml)
       (label foo)))
     (((f.ml (1 3) (1 6)) (word Foo)))))
   ((f.ml (2 0) (2 7))
    (1
     (label
      ((root (f.ml (page f.ml) 00000000000000000000000000000000) f.ml)
       (label bar)))
     (((f.ml (2 3) (2 6)) (word Bar)))))
   ((f.ml (3 0) (3 7))
    (2
     (label
      ((root (f.ml (page f.ml) 00000000000000000000000000000000) f.ml)
       (label baz)))
     (((f.ml (3 3) (3 6)) (word Baz)))))))
 (warnings
  ( "File \"f.ml\", line 2, characters 0-7:\
   \n'{1': heading level should be lower than top heading level '3'."
    "File \"f.ml\", line 3, characters 0-7:\
   \n'{2': heading level should be lower than top heading level '3'.")))
