データの正負を逆転させる
> let data = 100;; val data : int = 100 > let data' = -data;; val data' : int = -100 > let data'' = (~-) data;; val data'' : int = -100 > data |> (~-);; val it : int = -100 >
> let data = 100;; val data : int = 100 > let data' = -data;; val data' : int = -100 > let data'' = (~-) data;; val data'' : int = -100 > data |> (~-);; val it : int = -100 >