## Comments

    (* Simple comment *)
    (* Multi-line
    comment *)

## Numbers

    42
    3.14159
    42.
    2.4E+2
    10_452_102
    0xf4 0xff_10_41
    0o427
    0b1100_1111_0000

## Strings and characters

    "Simple string."
    "String with \"quotes\" in it."
    'c' `c`
    '\'' `\``
    '\123' `\123`
    '\xf4'

## Full example

    module Make_interval(Endpoint : Comparable) = struct

        type t = | Interval of Endpoint.t * Endpoint.t
                 | Empty

        (** [create low high] creates a new interval from [low] to
            [high].  If [low > high], then the interval is empty *)
        let create low high =
          if Endpoint.compare low high > 0 then Empty
          else Interval (low,high)

        (** Returns true iff the interval is empty *)
        let is_empty = function
          | Empty -> true
          | Interval _ -> false

        (** [contains t x] returns true iff [x] is contained in the
            interval [t] *)
        let contains t x =
          match t with
          | Empty -> false
          | Interval (l,h) ->
            Endpoint.compare x l >= 0 && Endpoint.compare x h <= 0

        (** [intersect t1 t2] returns the intersection of the two input
            intervals *)
        let intersect t1 t2 =
          let min x y = if Endpoint.compare x y <= 0 then x else y in
          let max x y = if Endpoint.compare x y >= 0 then x else y in
          match t1,t2 with
          | Empty, _ | _, Empty -> Empty
          | Interval (l1,h1), Interval (l2,h2) ->
            create (max l1 l2) (min h1 h2)

      end ;;