type token =
| Id of string
| Key of string
| Proof of string * string
| Word
| Eof
val open_file : string -> input
val close : input -> unit
val error :
input ->
('a, Stdlib.Format.formatter, unit, 'b) Stdlib.format4 ->
'a
val key : input -> string -> bool
val eat : input -> string -> unit
val ident : input -> string
val idents : input -> string list
val filter : string -> string option