module Update:sig..end
type | | | Data of  | (* | Warnings do not close the stream and whatever is reading can keep on doing so.
      The stringis the file name. | *) | 
| | | Warning of  | (* | Errors cause the stream to be closed.  The stringis the file name. | *) | 
| | | Error of  | 
val to_string_hum : t -> stringval sexp_of_t : t -> Sexplib.Sexp.t