(executable
 (name my_prog))

(rule
 (target my_coq_file.ml)
 (deps extraction/my_coq_file.ml)
 (action
  (with-stdout-to %{target}
  ; here you patch stuff
   (cat %{deps}))))

(copy_files extraction/Datatypes.ml)
(copy_files extraction/Datatypes.mli)
(copy_files extraction/my_coq_file.mli)
