lib/mlton/basic/ring.fun

   1 (* Copyright (C) 1999-2006 Henry Cejtin, Matthew Fluet, Suresh
   2  *    Jagannathan, and Stephen Weeks.
   3  *
   4  * MLton is released under a BSD-style license.
   5  * See the file MLton-LICENSE for details.
   6  *)
   7
   8 functor Ring(S: RING_STRUCTS):> RING where type t = S.t =
   9 struct
  10
  11 open S
  12
  13 fun a - b = a + (~ b)
  14
  15 fun isZero a = equals(a, zero)
  16
  17 fun double n = n + n
  18
  19 fun square n = n * n
  20
  21 fun sum l = List.fold(l, zero, op +)
  22
  23 end