Ajout Stack.top

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@3072 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

stdlib/stack.ml

@@ -27,6 +27,11 @@ let pop s =
     hd::tl -> s.c <- tl; hd
   | []     -> raise Empty
 
+let top s =
+  match s.c with
+    hd::_ -> hd
+  | []     -> raise Empty
+
 let length s = List.length s.c
 
 let iter f s = List.iter f s.c

stdlib/stack.mli

@@ -29,6 +29,9 @@ val push: 'a -> 'a t -> unit
 val pop: 'a t -> 'a
         (* [pop s] removes and returns the topmost element in stack [s],
            or raises [Empty] if the stack is empty. *)
+val top: 'a t -> 'a
+        (* [top s] returns the topmost element in stack [s],
+           or raises [Empty] if the stack is empty. *)
 val clear : 'a t -> unit
         (* Discard all elements from a stack. *)
 val length: 'a t -> int