new

html/cats.ml

@@ -1,70 +0,0 @@
-module type Functor = sig
-  type 'a t
-  val map : ('a -> 'b) -> 'a t -> 'b t
-end
-
-module type Applicative = sig
-  type 'a t
-  val pure : 'a -> 'a t
-  val apply : ('a -> 'b) t -> 'a t -> 'b t
-end
-
-module type Monad = sig
-  type 'a t
-  val return : 'a -> 'a t
-  val bind : ('a -> 'b t) -> 'a t -> 'b t
-end
-
-module ApplicativeOfMonad (M : Monad) : Applicative with type 'a t = 'a M.t = struct
-  type 'a t = 'a M.t
-  let pure = M.return
-  let apply f x = M.(bind (fun y -> bind (fun g -> return (g y)) f) x)
-end
-
-module FunctorOfApplicative (A : Applicative) : Functor with type 'a t = 'a A.t = struct
-  type 'a t = 'a A.t
-  let map f x = A.(apply (pure f) x)
-end
-
-module FunctorOfMonad (M : Monad) : Functor with type 'a t = 'a M.t = struct
-  include FunctorOfApplicative(ApplicativeOfMonad(M))
-end
-
-module MonadDerive (M : Monad) = struct
-  include M
-  include ApplicativeOfMonad(M)
-  include FunctorOfMonad(M)
-  let (>>=) x f = bind f x
-  let (<$>) x f = map x f
-  let (<*>) x f = apply x f
-end
-
-module ListMonad = struct
-  type 'a t = 'a list
-  let return x = [x]
-  let rec bind (f : 'a -> 'b list) : 'a list -> 'b list = function
-    | [] -> []
-    | x :: xs -> f x @ bind f xs
-end
-
-module Dlm = MonadDerive(ListMonad)
-
-let pair x y = x, y
-let cart_prod xs ys = Dlm.(pair <$> xs <*> ys)
-
-let () = cart_prod [1;2;3;4] ["7"; "hello there"; "forthwith!"]
-    |> List.iter (fun (x, y) -> print_endline @@ "(" ^ string_of_int x ^ ", " ^ y ^ ")")
-
-
-
-(* ============================================================================================= *)
-
-module StateMonad (S : sig type t end) = struct
-  type 'a t = S.t -> S.t * 'a
-  let return x s = (s, x)
-  let bind f x s = let s', a = x s in f a s'
-end
-
-module IntStateMonad = StateMonad(struct type t = int end)
-
-