b6449cae87
* `lib_stdlib`: basic extended OCaml stdlib and generic data structures * `lib_data_encoding`: almost independant 'Data_encoding' * `lib_error_monad`: almost independant 'Error_monad' * `lib_stdlib_lwt`: extended Lwt library * `lib_crypto`: all the crypto stuff (hashing, signing, cryptobox). * `lib_base`: - basic type definitions (Block_header, Operation, ...) - a module `TzPervasives` to bind them all and to be the single module opened everywhere. In the process, I splitted `Tezos_data` and `Hash` in multiple submodules, thus removing a lot of `-open`. The following two modules may not have found their place yet: - Base58 (currently in `lib_crypto`) - Cli_entries (currently in `lib_stdlib_lwt`)
54 lines
2.1 KiB
OCaml
54 lines
2.1 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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Test.run "utils." tests
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