[MLton-commit] r5020

[Vesa K. <ve...@ml...>]

Initial commit of a lib of misc utils to be refactored.
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A   mltonlib/trunk/com/ssh/misc-util/unstable/cache.sig

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Added: mltonlib/trunk/com/ssh/misc-util/unstable/cache.sig
===================================================================
--- mltonlib/trunk/com/ssh/misc-util/unstable/cache.sig	2007-01-12 12:24:34 UTC (rev 5019)
+++ mltonlib/trunk/com/ssh/misc-util/unstable/cache.sig	2007-01-12 12:24:45 UTC (rev 5020)
@@ -0,0 +1,46 @@
+(* Copyright (C) 2007 SSH Communications Security, Helsinki, Finland
+ *
+ * This code is released under the MLton license, a BSD-style license.
+ * See the LICENSE file or http://mlton.org/License for details.
+ *)
+
+(**
+ * Signature for an imperative polymorphic cache for storing values.  A cache
+ * differs from an ordinary imperative polymorphic map in that a cache
+ * automatically generates keys for values.
+ *)
+signature CACHE = sig
+   type 'a t
+
+   structure Key : sig
+      type t
+   end
+
+   exception NotFound
+   (** Raised by {get}, {use}, and {rem} in case a key is not found. *)
+
+   val new : Unit.t -> 'a t
+   (** Creates a new (empty) cache. *)
+
+   val size : 'a t -> Int.t
+   (** Returns the number of elements in the cache. *)
+
+   val putWith : 'a t -> (Key.t -> 'a) -> Key.t * 'a
+   (**
+    * Puts a key dependent value into cache and returns the key and
+    * value.  If the construction of the value raises an exception, the
+    * state of the cache does not change observably.
+    *)
+
+   val put : 'a t -> 'a -> Key.t
+   (** Puts a value into cache and return the key for the value. *)
+
+   val get : 'a t -> Key.t -> 'a
+   (** Returns the value corresponding to the key. *)
+
+   val use : 'a t -> Key.t -> 'a
+   (** Removes from the cache and returns the value corresponding to the key. *)
+
+   val rem : 'a t -> Key.t -> Unit.t
+   (** Removes from the cache the value corresponding to the key. *)
+end


Property changes on: mltonlib/trunk/com/ssh/misc-util/unstable/cache.sig
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Name: svn:eol-style
   + native