QCaml/ci/lib/phase.ml

type t =
| Pos
| Neg

let of_nperm nperm =
  if (nperm land 1) = 1 then Neg
  else Pos

let to_nperm = function
| Pos -> 0
| Neg -> 1

let multiply t t' =
  match t, t' with
  | Pos, Pos
  | Neg, Neg -> Pos
  | Pos, Neg
  | Neg, Pos -> Neg

let neg = function
  | Pos -> Neg
  | Neg -> Pos

let add_nperm phase = function
  | 0 -> phase
  | nperm -> multiply phase (of_nperm nperm)

let pp ppf = function
  | Pos -> Format.fprintf ppf "@[<h>+1@]"
  | Neg -> Format.fprintf ppf "@[<h>-1@]"