{ type result = Int of int | Float of float | String of string }

let digit = ['0'-'9']
let digits = digit +
let lower_case = ['a'-'z']
let upper_case = ['A'-'Z']
let letter = upper_case | lower_case
let letters = letter +

rule main = parse
   (digits)'.' digits as f  { Float (float_of_string f) }
 | digits as n              { Int (int_of_string n) }
 | letters as s             { String s}
 | _ { main lexbuf }

{ let newlexbuf = (Lexing.from_channel stdin) in
   print_string "Ready to lex.";
   print_newline ();
   main newlexbuf  }