details

core/CCKList.ml

@@ -33,9 +33,14 @@ type + 'a t =
 
 let nil = `Nil
 let cons a b = `Cons (a,b)
+let empty = nil
 
 let singleton x = `Cons (x, fun () -> `Nil)
 
+let is_empty = function
+  | `Nil -> true
+  | `Cons _ -> false
+
 let to_list l =
   let rec direct i (l:'a t) = match l with
     | `Nil -> []

core/CCKList.mli

@@ -32,10 +32,14 @@ type + 'a t =
 
 val nil : 'a t
 
+val empty : 'a t
+
 val cons : 'a -> (unit -> 'a t) -> 'a t
 
 val singleton : 'a -> 'a t
 
+val is_empty : 'a t -> bool
+
 val of_list : 'a list -> 'a t
 
 val to_list : 'a t -> 'a list