Ajout de List.for_all2 et List.exists2.

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@299 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

stdlib/list.ml

@@ -91,6 +91,18 @@ let rec exists p = function
     [] -> false
   | a::l -> p a or exists p l
 
+let rec for_all2 p l1 l2 =
+  match (l1, l2) with
+    ([], []) -> true
+  | (a1::l1, a2::l2) -> p a1 a2 & for_all2 p l1 l2
+  | (_, _) -> invalid_arg "List.for_all2"
+
+let rec exists2 p l1 l2 =
+  match (l1, l2) with
+    ([], []) -> true
+  | (a1::l1, a2::l2) -> p a1 a2 or exists2 p l1 l2
+  | (_, _) -> invalid_arg "List.exists2"
+
 let rec mem x = function
     [] -> false
   | a::l -> a = x or mem x l

stdlib/list.mli

@@ -77,9 +77,14 @@ val for_all : ('a -> bool) -> 'a list -> bool
            satisfy the predicate [p]. That is, it returns
            [(p a1) & (p a2) & ... & (p an)]. *)
 val exists : ('a -> bool) -> 'a list -> bool
-        (* [exists p [a1; ...; an]] checks if at least one element of the list
-           satisfies the predicate [p]. That is, it returns
+        (* [exists p [a1; ...; an]] checks if at least one element of
+           the list satisfies the predicate [p]. That is, it returns
            [(p a1) or (p a2) or ... or (p an)]. *)
+val for_all2 : ('a -> 'b -> bool) -> 'a list -> 'b list -> bool
+val exists2 : ('a -> 'b -> bool) -> 'a list -> 'b list -> bool
+        (* Same as [for_all] and [exists], but for a two-argument predicate.
+           Raise [Invalid_argument] if the two lists have
+	   different lengths. *)
 val mem : 'a -> 'a list -> bool
         (* [mem a l] is true if and only if [a] is equal
            to an element of [l]. *)