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52 lines
989 B
52 lines
989 B
(*
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*)
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include Monad_intf
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module Make (M : sig
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type 'a t
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val return : 'a -> 'a t
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val bind : 'a t -> ('a -> 'b t) -> 'b t
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end) =
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struct
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include M
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let map f m = bind m (fun a -> return (f a))
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let ap m n = bind m (fun f -> bind n (fun a -> return (f a)))
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let prod m n = bind m (fun a -> bind n (fun b -> return (a, b)))
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module Import = struct
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let ( |>= ) m f = map f m
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let ( >>= ) = bind
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let ( let* ) = bind
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let ( and* ) = prod
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let ( let+ ) = ( |>= )
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let ( and+ ) = prod
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end
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let bind m ~f = bind m f
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let map m ~f = map f m
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end
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module State (State : sig
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type t
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end) =
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struct
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include Make (struct
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type 'a t = State.t -> 'a * State.t
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let return a s = (a, s)
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let bind m k s =
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let a, s = m s in
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k a s
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end)
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let run m s = m s
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end
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