2 files changed, 45 insertions, 0 deletions
diff --git a/lib/Utilities.ml b/lib/Utilities.ml
index a6b36c7..e4ee9c3 100644
--- a/lib/Utilities.ml
+++ b/lib/Utilities.ml
@@ -1,3 +1,9 @@
+module Ordering = struct
+  type t = Equal | Smaller | Greater
+
+  let of_int x = if x < 0 then Smaller else if x > 0 then Greater else Equal
+end
+
 module Result = struct
   let ( let* ) = Result.bind
   let fmap f m = Result.bind m f
@@ -69,3 +75,25 @@ module FingerTree = struct
     BatFingerTree.print ~first:"" ~last:"" ~sep:sep BatIO.nwrite
     |> Fun.flip BatIO.to_string ss
 end
+
+module Option = struct
+  let ( let* ) = Option.bind
+  let fmap f m = Option.bind m f
+end
+
+module Atomic = struct
+  let rec swap atom f =
+    let v = Atomic.get atom in
+    let v' = f v in
+    if Atomic.compare_and_set atom v v'
+    then atom
+    else swap atom f
+
+  let rec mswap atom f =
+    let open Result in
+    let v = Atomic.get atom in
+    let* v' = f v in
+    if Atomic.compare_and_set atom v v'
+    then Ok atom
+    else mswap atom f
+end
diff --git a/lib/Utilities.mli b/lib/Utilities.mli
index 2735009..f149889 100644
--- a/lib/Utilities.mli
+++ b/lib/Utilities.mli
@@ -1,3 +1,9 @@
+module Ordering : sig
+  type t = Equal | Smaller | Greater
+
+  val of_int : int -> t
+end
+
 module Result : sig
   val ( let* ) : ('a, 'e) result -> ('a -> ('b, 'e) result) -> ('b, 'e) result
   val fmap : ('a -> ('b, 'e) result) -> ('a, 'e) result -> ('b, 'e) result
@@ -7,6 +13,17 @@ module List : sig
   val sequence : ('a, 'b) result list -> ('a list, 'b) result
 end
 
+module Option : sig
+  val ( let* ) : 'a option -> ('a -> 'b option) -> 'b option
+  val fmap : ('a -> 'b option) -> 'a option -> 'b option
+end
+
+module Atomic : sig
+  val swap : 'a Atomic.t -> ('a -> 'a) -> 'a Atomic.t
+  (* This is silly *)
+  val mswap : 'a Atomic.t -> ('a -> ('a, 'b) result) -> ('a Atomic.t, 'b) result
+end
+
 module FingerTree : sig
   val map2 : ('a -> 'b -> 'c) -> 'a BatFingerTree.t -> 'b BatFingerTree.t -> 'c BatFingerTree.t
   val zip : 'a BatFingerTree.t -> 'b BatFingerTree.t -> ('a * 'b) BatFingerTree.t