ajout Weak.check

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@2181 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

stdlib/weak.ml

@@ -23,6 +23,8 @@ external set : 'a t -> int -> 'a option -> unit = "weak_set";;
 
 external get: 'a t -> int -> 'a option = "weak_get";;
 
+external check: 'a t -> int -> bool = "weak_check";;
+
 let fill ar ofs len x =
   if ofs < 0 || ofs + len > length ar
   then raise (Invalid_argument "Weak.fill")

stdlib/weak.mli

@@ -42,6 +42,11 @@ val get : 'a t -> int -> 'a option;;
            Raise [Invalid_argument "Weak.get"] if [n] is not in the range
            0 to [Weak.length a - 1].
          *)
+val check: 'a t -> int -> bool;;
+        (* [Weak.check ar n] returns [true] if the [n]th cell of [ar] is
+           full, [false] if it is empty.  Note that even if [Weak.check ar n]
+           returns [true], a subsequent [Weak.get ar n] can return [None].
+        *)
 val fill: 'a t -> int -> int -> 'a option -> unit;;
         (* [Weak.fill ar ofs len el] sets to [el] all pointers of [ar] from
            [ofs] to [ofs + len - 1].  Raise [Invalid_argument "Weak.fill"]