feat(CCArray): add optional argument eq to mem

src/core/CCArray.ml

@@ -197,8 +197,21 @@ let rev a =
   rev [| |] = [| |]
 *)
 
+exception Found
+
+let mem ?(eq = Stdlib.(=)) elt a =
+  try
+    Array.iter (fun e -> if eq e elt then raise Found) a;
+    false
+  with Found -> true
+
+(*$Q mem
+  Q.(array small_int) (fun a -> \
+  mem 1 a = (Array.mem 1 a))
+*)
+
 let rec find_aux f a i =
-  if i = Array.length a then None
+  if i >= Array.length a then None
   else match f i a.(i) with
     | Some _ as res -> res
     | None -> find_aux f a (i+1)

src/core/CCArray.mli

@@ -132,6 +132,9 @@ val sort_ranking : ('a -> 'a -> int) -> 'a t -> int array
     [lookup_exn a.(i) (sorted a) = (sorted_ranking a).(i)].
     @since 1.0 *)
 
+val mem : ?eq:('a -> 'a -> bool) -> 'a -> 'a t -> bool
+(** [mem ~eq x a] return true if x is present in [a]. Linear time. *)
+
 val find_map : ('a -> 'b option) -> 'a t -> 'b option
 (** [find_map f a] returns [Some y] if there is an element [x] such
     that [f x = Some y]. Otherwise returns [None].

src/core/CCArrayLabels.mli

@@ -131,6 +131,9 @@ val sort_ranking : f:('a -> 'a -> int) -> 'a t -> int array
     [lookup_exn a.(i) (sorted a) = (sorted_ranking a).(i)].
     @since 1.0 *)
 
+val mem : ?eq:('a -> 'a -> bool) -> 'a -> 'a t -> bool
+(** [mem ~eq x a] return true if x is present in [a]. Linear time. *)
+
 val find_map : f:('a -> 'b option) -> 'a t -> 'b option
 (** [find_map ~f a] returns [Some y] if there is an element [x] such
     that [~f x = Some y]. Otherwise returns [None].