[hcoop/debian/mlton.git] / lib / mlton / basic / counter.sml

(* Copyright (C) 2009 Matthew Fluet.
 * Copyright (C) 1999-2006 Henry Cejtin, Matthew Fluet, Suresh
 *    Jagannathan, and Stephen Weeks.
 *
 * MLton is released under a BSD-style license.
 * See the file MLton-LICENSE for details.
 *)

structure Counter: COUNTER =
struct

datatype t = T of int ref

fun new n = T(ref n)

fun reset(T r, n) = r := n

fun tick(T r) = Int.inc r

fun value(T r) = !r

fun next c = value c before tick c

val equals = fn (T r, T r') => r = r'

end
Commit	Line	Data
7f918cf1 CE	1	(* Copyright (C) 2009 Matthew Fluet.
	2	* Copyright (C) 1999-2006 Henry Cejtin, Matthew Fluet, Suresh
	3	* Jagannathan, and Stephen Weeks.
	4	*
	5	* MLton is released under a BSD-style license.
	6	* See the file MLton-LICENSE for details.
	7	*)
	8
	9	structure Counter: COUNTER =
	10	struct
	11
	12	datatype t = T of int ref
	13
	14	fun new n = T(ref n)
	15
	16	fun reset(T r, n) = r := n
	17
	18	fun tick(T r) = Int.inc r
	19
	20	fun value(T r) = !r
	21
	22	fun next c = value c before tick c
	23
	24	val equals = fn (T r, T r') => r = r'
	25
	26	end