54 lines
1.9 KiB
Text
54 lines
1.9 KiB
Text
/-
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Copyright (c) 2020 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, Mario Carneiro
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-/
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prelude
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import Init.Tactics
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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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Replaces the element at a given index in an array.
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No bounds check is performed, but the function requires a proof that the index is in bounds. This
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proof can usually be omitted, and will be synthesized automatically.
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The array is modified in-place if there are no other references to it.
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Examples:
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* `#[0, 1, 2].set 1 5 = #[0, 5, 2]`
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* `#["orange", "apple"].set 1 "grape" = #["orange", "grape"]`
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-/
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@[extern "lean_array_fset"]
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def Array.set (xs : Array α) (i : @& Nat) (v : α) (h : i < xs.size := by get_elem_tactic) :
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Array α where
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toList := xs.toList.set i v
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/--
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Replaces the element at the provided index in an array. The array is returned unmodified if the
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index is out of bounds.
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The array is modified in-place if there are no other references to it.
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Examples:
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* `#[0, 1, 2].setIfInBounds 1 5 = #[0, 5, 2]`
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* `#["orange", "apple"].setIfInBounds 1 "grape" = #["orange", "grape"]`
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* `#["orange", "apple"].setIfInBounds 5 "grape" = #["orange", "apple"]`
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-/
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@[inline] def Array.setIfInBounds (xs : Array α) (i : Nat) (v : α) : Array α :=
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dite (LT.lt i xs.size) (fun h => xs.set i v h) (fun _ => xs)
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@[deprecated Array.setIfInBounds (since := "2024-11-24")] abbrev Array.setD := @Array.setIfInBounds
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/--
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Set an element in an array, or panic if the index is out of bounds.
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This will perform the update destructively provided that `a` has a reference
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count of 1 when called.
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-/
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@[extern "lean_array_set"]
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def Array.set! (xs : Array α) (i : @& Nat) (v : α) : Array α :=
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Array.setIfInBounds xs i v
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