Add List.remove_last

src/core/CCList.ml

@@ -1109,6 +1109,17 @@ let remove_at_idx i l0 =
   remove_at_idx 5 [1;2;3;4] = [1;2;3;4]
 *)
 
+let rec remove_last = function
+  | [] | [_] -> []
+  | x::xs -> x::remove_last xs
+
+(*$T
+  remove_last [] = []
+  remove_last [1] = []
+  remove_last [1; 2] = [1]
+  remove_last [1; 2; 3] = [1; 2]
+*)
+
 let range_by ~step i j =
   let rec range i j acc =
     if i=j then i::acc else range i (j-step) (j::acc)

src/core/CCList.mli

@@ -261,6 +261,11 @@ val remove : ?eq:('a -> 'a -> bool) -> x:'a -> 'a t -> 'a t
     @param eq equality function
     @since 0.11 *)
 
+val remove_last : 'a list -> 'a list
+(** [remove_last l] removes the last element of [l]. If [l] is empty,
+    an empty list will be returned.
+    @since NEXT_RELEASE *)
+
 val filter_map : ('a -> 'b option) -> 'a t -> 'b t
 (** Map and remove elements at the same time *)