diff --git a/core/CCHash.ml b/core/CCHash.ml
index 5c6b3885..9432b588 100644
--- a/core/CCHash.ml
+++ b/core/CCHash.ml
@@ -69,9 +69,15 @@ let rec list_ f l s = match l with
 
 let array_ f a s = Array.fold_right f a s
 
+let opt f o h = match o with
+  | None -> h
+  | Some x -> f x h
 let pair h1 h2 (x,y) s = h2 y (h1 x s)
 let triple h1 h2 h3 (x,y,z) s = h3 z (h2 y (h1 x s))
 
+let if_ b then_ else_ h =
+  if b then then_ h else else_ h
+
 type 'a sequence = ('a -> unit) -> unit
 type 'a gen = unit -> 'a option
 type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]
diff --git a/core/CCHash.mli b/core/CCHash.mli
index 33c56263..279c21f2 100644
--- a/core/CCHash.mli
+++ b/core/CCHash.mli
@@ -61,9 +61,13 @@ val list_ : 'a hash_fun -> 'a list hash_fun
 
 val array_ : 'a hash_fun -> 'a array hash_fun
 
+val opt : 'a hash_fun -> 'a option hash_fun
 val pair : 'a hash_fun -> 'b hash_fun -> ('a * 'b) hash_fun
 val triple : 'a hash_fun -> 'b hash_fun -> 'c hash_fun -> ('a * 'b * 'c) hash_fun
 
+val if_ : bool -> 'a hash_fun -> 'a hash_fun -> 'a hash_fun
+(** Decide which hash function to use depending on the boolean *)
+
 type 'a sequence = ('a -> unit) -> unit
 type 'a gen = unit -> 'a option
 type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]