open Printf;;
open Stream;;
type sign =
    Plus
    | Minus;;

type atom =

    T
    |   NIL
    |   Int of int
    |  Ident of string;;

type token =

Lparen
    |  Rparen
    |  Dot
    |  Sign of sign
    |  Atom of atom;;
Stream.t char s from "lines.txt";;
let rec spaces s=

match s with parser
    [< '' '|' 't' | 'n' ; _ >] -> spaces s (* ERROR HERE ON '[<' *)
    |  [<  >]  -> ()

;;

let rec lexid str s =

    match s with parser

        [< ' 'a'..'z'| 'A'....'Z'| '0'...'9' as c; _ >] -> lexid (str ^     (Char.escaped c)) s

| [< >] -> str;;
let rec lexint v s=
    match s with parser
    [< ‘’0’..’9’ as n; _ >] -> lexint ((10*v)+(int_of_string(Char.escaped n))) s
    | [< >] -> v
;;