(*
  Source:  https://github.com/io7m/jsom0
  License: ISC
*)

digit_without_zero =
  "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" ;

digit =
  "0" | digit_without_zero ;

positive =
  digit_without_zero , { digit } ;

natural =
  "0" | positive ;

real =
  [ "-" ] , digit , [ "." , { digit } ] ;