(* This type should be used for all charges in the program (electrons, nuclei,...). *)
type t = float

(** Conversions *)
external of_float : float -> t = "%identity"
external to_float : t -> float = "%identity"

let of_int = float_of_int
let to_int = int_of_float

let of_string = float_of_string

let to_string x =
  if x >  0. then
    Printf.sprintf "+%f" x
  else if x < 0. then
    Printf.sprintf "%f" x
  else
    "0.0"

(** Simple operations *)
let gen_op op =
  fun a b ->
  op (to_float a) (to_float b)
  |> of_float

let ( + ) = gen_op ( +. )
let ( - ) = gen_op ( -. )
let ( * ) = gen_op ( *. )
let ( / ) = gen_op ( /. )

let is_null t = t == 0.

(** Printers *)
let pp ppf x =
  Format.fprintf ppf "@[%s@]" (to_string x)