09a5b34931
This PR adjusts the experimental module system to make `private` the default visibility modifier in `module`s, introducing `public` as a new modifier instead. `public section` can be used to revert the default for an entire section, though this is more intended to ease gradual adoption of the new semantics such as in `Init` (and soon `Std`) where they should be replaced by a future decl-by-decl re-review of visibilities.
41 lines
1.4 KiB
Text
41 lines
1.4 KiB
Text
/-
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Copyright (c) 2018 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Authors: Leonardo de Moura
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-/
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module
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prelude
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public import Init.Data.Array.Basic
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public section
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set_option linter.listVariables true -- Enforce naming conventions for `List`/`Array`/`Vector` variables.
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set_option linter.indexVariables true -- Enforce naming conventions for index variables.
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/--
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Sorts an array using insertion sort.
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The optional parameter `lt` specifies an ordering predicate. It defaults to `LT.lt`, which must be
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decidable to be used for sorting.
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-/
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@[inline] def Array.insertionSort (xs : Array α) (lt : α → α → Bool := by exact (· < ·)) : Array α :=
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traverse xs 0 xs.size
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where
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@[specialize] traverse (xs : Array α) (i : Nat) (fuel : Nat) : Array α :=
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match fuel with
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| 0 => xs
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| fuel+1 =>
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if h : i < xs.size then
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traverse (swapLoop xs i h) (i+1) fuel
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else
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xs
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@[specialize] swapLoop (xs : Array α) (j : Nat) (h : j < xs.size) : Array α :=
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match (generalizing := false) he:j with -- using `generalizing` because we don't want to refine the type of `h`
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| 0 => xs
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| j'+1 =>
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have h' : j' < xs.size := by subst j; exact Nat.lt_trans (Nat.lt_succ_self _) h
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if lt xs[j] xs[j'] then
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swapLoop (xs.swap j j') j' (by rw [size_swap]; assumption; done)
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else
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xs
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