55 lines
2.2 KiB
OCaml
55 lines
2.2 KiB
OCaml
(**************************************************************************)
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(* *)
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(* Copyright (c) 2014 - 2017. *)
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(* Dynamic Ledger Solutions, Inc. <contact@tezos.com> *)
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(* *)
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(* All rights reserved. No warranty, explicit or implicit, provided. *)
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(* *)
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(**************************************************************************)
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let rec permut = function
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| [] -> [[]]
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| x :: xs ->
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let insert xs =
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let rec loop acc left right =
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match right with
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| [] -> List.rev (x :: left) :: acc
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| y :: ys ->
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loop
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((List.rev_append left (x :: right)) :: acc)
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(y :: left) ys in
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loop [] [] xs in
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List.concat (List.map insert (permut xs))
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let test_take_n _ =
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ListLabels.iter (permut [1;2;3;4;5;6;7;8;9]) ~f:begin fun xs ->
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Assert.equal ~msg:__LOC__ (List.take_n ~compare 1 xs) [9]
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end ;
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ListLabels.iter (permut [1;2;3;4;5;6;7;8;9]) ~f:begin fun xs ->
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Assert.equal ~msg:__LOC__ (List.take_n ~compare 3 xs) [7;8;9]
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end ;
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let inv_compare x y = compare y x in
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ListLabels.iter (permut [1;2;3;4;5;6;7;8;9]) ~f:begin fun xs ->
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Assert.equal ~msg:__LOC__ (List.take_n ~compare:inv_compare 3 xs) [3;2;1]
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end ;
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(* less elements than the bound. *)
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ListLabels.iter (permut [1;2;3;4;5;6;7;8;9]) ~f:begin fun xs ->
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Assert.equal ~msg:__LOC__ (List.take_n ~compare 12 xs) [1;2;3;4;5;6;7;8;9]
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end ;
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(* with duplicates. *)
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ListLabels.iter (permut [1;2;3;3;4;5;5;5;6]) ~f:begin fun xs ->
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Assert.equal ~msg:__LOC__ (List.take_n ~compare 3 xs) [5;5;6]
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end ;
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ListLabels.iter (permut [1;2;3;3;4;5;5;5;6]) ~f:begin fun xs ->
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Assert.equal ~msg:__LOC__ (List.take_n ~compare 5 xs) [4;5;5;5;6]
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end ;
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return ()
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let tests : (string * (string -> unit tzresult Lwt.t)) list = [
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"take_n", test_take_n ;
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]
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let () =
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let module Test = Tezos_test_helpers.Test.Make(Error_monad) in
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Test.run "utils." tests
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