type token =
  | IDENT of (Fol.ident)
  | PLUS
  | MOINS
  | PLUSPLUS
  | INTER
  | FLECHE
  | CROCHETG
  | CROCHETD
  | RESTD
  | RESTG
  | POINT
  | TILDE
  | PARG
  | PARD
  | UNIV
  | IDEN
  | NONE
  | BARRE
  | IF
  | THEN
  | ELSE
  | LET
  | VIRGULE
  | EQ
  | OR
  | IMPLIES
  | AND
  | NOT
  | SOME
  | NO
  | LONE
  | ONE
  | IN
  | ALL
  | ACCG
  | ACCD
  | DP
  | SET
  | DIV
  | SIG
  | ABSTRACT
  | EXTENDS
  | PRED
  | FUN
  | FACT
  | ASSERT
  | CHECK
  | RUN
  | OPEN
  | MODULE
  | EXACTLY
  | FOR
  | BUT
  | INT
  | LT
  | GT
  | EOF
  | EXPECTS

val modul :
  (Lexing.lexbuf  -> token) -> Lexing.lexbuf -> (token Fol.env -> token Fol.env)