lean4-htt/src/Init/Data/List/ToArray.lean
2025-10-26 10:01:30 +00:00

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/-
Copyright (c) 2022 Mario Carneiro. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Mario Carneiro
-/
module
prelude
import all Init.Data.List.Control
public import Init.Data.List.Monadic
public import Init.Data.List.Nat.InsertIdx
import all Init.Data.Array.Basic
import all Init.Data.Array.Set
public section
/-! ### Lemmas about `List.toArray`.
We prefer to pull `List.toArray` outwards past `Array` operations.
-/
set_option linter.listVariables true -- Enforce naming conventions for `List`/`Array`/`Vector` variables.
set_option linter.indexVariables true -- Enforce naming conventions for index variables.
namespace Array
@[simp] theorem toList_set (xs : Array α) (i x h) :
(xs.set i x).toList = xs.toList.set i x := rfl
theorem swap_def (xs : Array α) (i j : Nat) (hi hj) :
xs.swap i j hi hj = (xs.set i xs[j]).set j xs[i] (by simpa using hj) := by
simp [swap]
@[simp] theorem toList_swap (xs : Array α) (i j : Nat) (hi hj) :
(xs.swap i j hi hj).toList = (xs.toList.set i xs[j]).set j xs[i] := by simp [swap_def]
end Array
namespace List
open Array
theorem toArray_inj {as bs : List α} (h : as.toArray = bs.toArray) : as = bs := by
cases as with
| nil => simpa using h
| cons a as =>
cases bs with
| nil => simp at h
| cons b bs => simpa using h
theorem toArray_eq_iff {as : List α} {bs : Array α} : as.toArray = bs ↔ as = bs.toList := by
cases bs
simp
-- We can't make this a `@[simp]` lemma because `#[] = [].toArray` at reducible transparency,
-- so this would loop with `toList_eq_nil_iff`
theorem eq_toArray_iff {as : Array α} {bs : List α} : as = bs.toArray ↔ as.toList = bs := by
cases as
simp
@[simp] theorem size_toArrayAux {as : List α} {xs : Array α} :
(as.toArrayAux xs).size = xs.size + as.length := by
simp [size]
-- This is not a `@[simp]` lemma because it is pushing `toArray` inwards.
theorem toArray_cons (a : α) (l : List α) : (a :: l).toArray = #[a] ++ l.toArray := by
apply ext'
simp
@[simp, grind =] theorem push_toArray (l : List α) (a : α) : l.toArray.push a = (l ++ [a]).toArray := by
apply ext'
simp
/-- Unapplied variant of `push_toArray`, useful for monadic reasoning. -/
@[simp] theorem push_toArray_fun (l : List α) : l.toArray.push = fun a => (l ++ [a]).toArray := by
funext a
simp
@[simp, grind =] theorem isEmpty_toArray (l : List α) : l.toArray.isEmpty = l.isEmpty := by
cases l <;> simp [Array.isEmpty]
@[simp] theorem toArray_singleton (a : α) : (List.singleton a).toArray = Array.singleton a := rfl
@[simp, grind =] theorem back!_toArray [Inhabited α] (l : List α) : l.toArray.back! = l.getLast! := by
simp only [back!, size_toArray, getElem!_toArray, getLast!_eq_getElem!]
@[simp, grind =] theorem back?_toArray (l : List α) : l.toArray.back? = l.getLast? := by
simp [back?, List.getLast?_eq_getElem?]
@[simp, grind =] theorem back_toArray (l : List α) (h) :
l.toArray.back = l.getLast (by simp at h; exact ne_nil_of_length_pos h) := by
simp [back, List.getLast_eq_getElem]
@[simp, grind =] theorem _root_.Array.getLast!_toList [Inhabited α] (xs : Array α) :
xs.toList.getLast! = xs.back! := by
rcases xs with ⟨xs⟩
simp
@[simp, grind =] theorem _root_.Array.getLast?_toList (xs : Array α) :
xs.toList.getLast? = xs.back? := by
rcases xs with ⟨xs⟩
simp
@[simp, grind =] theorem _root_.Array.getLast_toList (xs : Array α) (h) :
xs.toList.getLast h = xs.back (by simpa [ne_nil_iff_length_pos] using h) := by
rcases xs with ⟨xs⟩
simp
@[simp, grind =] theorem set_toArray (l : List α) (i : Nat) (a : α) (h : i < l.length) :
(l.toArray.set i a) = (l.set i a).toArray := rfl
@[simp] theorem forIn'_loop_toArray [Monad m] (l : List α) (f : (a : α) → a ∈ l.toArray → β → m (ForInStep β)) (i : Nat)
(h : i ≤ l.length) (b : β) :
Array.forIn'.loop l.toArray f i h b =
forIn' (l.drop (l.length - i)) b (fun a m b => f a (by simpa using mem_of_mem_drop m) b) := by
induction i generalizing l b with
| zero =>
simp [Array.forIn'.loop]
| succ i ih =>
simp only [Array.forIn'.loop, size_toArray, getElem_toArray, ih]
have t : drop (l.length - (i + 1)) l = l[l.length - i - 1] :: drop (l.length - i) l := by
simp only [Nat.sub_add_eq]
rw [List.drop_sub_one (by omega), List.getElem?_eq_getElem (by omega)]
simp only [Option.toList_some, singleton_append]
simp [t]
have t : l.length - 1 - i = l.length - i - 1 := by omega
simp only [t]
congr
@[simp, grind =] theorem forIn'_toArray [Monad m] (l : List α) (b : β) (f : (a : α) → a ∈ l.toArray → β → m (ForInStep β)) :
forIn' l.toArray b f = forIn' l b (fun a m b => f a (mem_toArray.mpr m) b) := by
change Array.forIn' _ _ _ = List.forIn' _ _ _
rw [Array.forIn', forIn'_loop_toArray]
simp
@[simp, grind =] theorem forIn_toArray [Monad m] (l : List α) (b : β) (f : α → β → m (ForInStep β)) :
forIn l.toArray b f = forIn l b f := by
simpa using forIn'_toArray l b fun a m b => f a b
@[grind =] theorem foldrM_toArray [Monad m] (f : α → β → m β) (init : β) (l : List α) :
l.toArray.foldrM f init = l.foldrM f init := by
rw [foldrM_eq_reverse_foldlM_toList]
simp
@[grind =] theorem foldlM_toArray [Monad m] (f : β → α → m β) (init : β) (l : List α) :
l.toArray.foldlM f init = l.foldlM f init := by
rw [foldlM_toList]
@[grind =] theorem foldr_toArray (f : α → β → β) (init : β) (l : List α) :
l.toArray.foldr f init = l.foldr f init := by
rw [foldr_toList]
@[grind =] theorem foldl_toArray (f : β → α → β) (init : β) (l : List α) :
l.toArray.foldl f init = l.foldl f init := by
rw [foldl_toList]
/-- Variant of `foldrM_toArray` with a side condition for the `start` argument. -/
@[simp] theorem foldrM_toArray' [Monad m] (f : α → β → m β) (init : β) (l : List α)
(h : start = l.toArray.size) :
l.toArray.foldrM f init start 0 = l.foldrM f init := by
subst h
rw [foldrM_eq_reverse_foldlM_toList]
simp
/-- Variant of `foldlM_toArray` with a side condition for the `stop` argument. -/
@[simp] theorem foldlM_toArray' [Monad m] (f : β → α → m β) (init : β) (l : List α)
(h : stop = l.toArray.size) :
l.toArray.foldlM f init 0 stop = l.foldlM f init := by
subst h
rw [foldlM_toList]
/-- Variant of `forM_toArray` with a side condition for the `stop` argument. -/
@[simp] theorem forM_toArray' [Monad m] (l : List α) (f : α → m PUnit) (h : stop = l.toArray.size) :
(l.toArray.forM f 0 stop) = l.forM f := by
subst h
rw [Array.forM]
simp only [size_toArray, foldlM_toArray']
induction l <;> simp_all
@[simp, grind =]
theorem forM_toArray [Monad m] (l : List α) (f : α → m PUnit) :
(forM l.toArray f) = l.forM f :=
forM_toArray' l f rfl
/-- Variant of `foldr_toArray` with a side condition for the `start` argument. -/
@[simp] theorem foldr_toArray' (f : α → β → β) (init : β) (l : List α)
(h : start = l.toArray.size) :
l.toArray.foldr f init start 0 = l.foldr f init := by
subst h
rw [foldr_toList]
/-- Variant of `foldl_toArray` with a side condition for the `stop` argument. -/
@[simp] theorem foldl_toArray' (f : β → α → β) (init : β) (l : List α)
(h : stop = l.toArray.size) :
l.toArray.foldl f init 0 stop = l.foldl f init := by
subst h
rw [foldl_toList]
@[simp, grind =] theorem sum_toArray [Add α] [Zero α] (l : List α) : l.toArray.sum = l.sum := by
simp [Array.sum, List.sum]
@[simp, grind =] theorem append_toArray (l₁ l₂ : List α) :
l₁.toArray ++ l₂.toArray = (l₁ ++ l₂).toArray := by
apply ext'
simp
@[simp] theorem push_append_toArray {as : Array α} {a : α} {bs : List α} : as.push a ++ bs.toArray = as ++ (a :: bs).toArray := by
cases as
simp
@[simp, grind =] theorem findSomeM?_toArray [Monad m] [LawfulMonad m] (f : α → m (Option β)) (l : List α) :
l.toArray.findSomeM? f = l.findSomeM? f := by
rw [Array.findSomeM?]
simp only [bind_pure_comp, map_pure, forIn_toArray]
induction l with
| nil => simp
| cons a l ih =>
simp only [forIn_cons, LawfulMonad.bind_assoc, findSomeM?]
congr
ext1 (_|_) <;> simp [ih]
private theorem findSomeRevM?_find_toArray [Monad m] [LawfulMonad m] (f : α → m (Option β)) (l : List α)
(i : Nat) (h) :
findSomeRevM?.find f l.toArray i h = (l.take i).reverse.findSomeM? f := by
induction i generalizing l with
| zero => simp [Array.findSomeRevM?.find]
| succ i ih =>
rw [size_toArray] at h
rw [Array.findSomeRevM?.find, take_succ, getElem?_eq_getElem (by omega)]
simp only [ih, reverse_append]
congr
ext1 (_|_) <;> simp
-- This is not marked as `@[simp]` as later we simplify all occurrences of `findSomeRevM?`.
theorem findSomeRevM?_toArray [Monad m] [LawfulMonad m] (f : α → m (Option β)) (l : List α) :
l.toArray.findSomeRevM? f = l.reverse.findSomeM? f := by
simp [Array.findSomeRevM?, findSomeRevM?_find_toArray]
-- This is not marked as `@[simp]` as later we simplify all occurrences of `findRevM?`.
theorem findRevM?_toArray [Monad m] [LawfulMonad m] (f : α → m Bool) (l : List α) :
l.toArray.findRevM? f = l.reverse.findM? f := by
rw [Array.findRevM?, findSomeRevM?_toArray, findM?_eq_findSomeM?]
@[simp, grind =] theorem findM?_toArray [Monad m] [LawfulMonad m] (f : α → m Bool) (l : List α) :
l.toArray.findM? f = l.findM? f := by
rw [Array.findM?]
simp only [bind_pure_comp, map_pure, forIn_toArray]
induction l with
| nil => simp
| cons a l ih =>
simp only [forIn_cons, LawfulMonad.bind_assoc, findM?]
congr
ext1 (_|_) <;> simp [ih]
@[simp, grind =] theorem findSome?_toArray (f : α → Option β) (l : List α) :
l.toArray.findSome? f = l.findSome? f := by
rw [Array.findSome?, findSomeM?_toArray, findSomeM?_pure, Id.run_pure]
@[simp, grind =] theorem find?_toArray (f : α → Bool) (l : List α) :
l.toArray.find? f = l.find? f := by
rw [Array.find?]
simp only [forIn_toArray]
induction l with
| nil => simp
| cons a l ih =>
simp only [forIn_cons, find?]
by_cases f a <;> simp_all
private theorem findFinIdx?_loop_toArray (w : l' = l.drop j) :
Array.findFinIdx?.loop p l.toArray j = List.findFinIdx?.go p l l' j h := by
unfold findFinIdx?.loop
unfold findFinIdx?.go
split <;> rename_i h'
· cases l' with
| nil =>
simp at h h'
omega
| cons a l' =>
have : l[j] = a := by
rw [drop_eq_getElem_cons] at w
simp only [cons.injEq] at w
exact w.1.symm
simp only [getElem_toArray, this]
split
· rfl
· simp only [length_cons] at h
have : l.length - (j + 1) < l.length - j := by omega
rw [findFinIdx?_loop_toArray]
rw [drop_add_one_eq_tail_drop, ← w, tail_cons]
· have : l' = [] := by simp_all
subst this
simp
termination_by l.length - j
@[simp, grind =] theorem findFinIdx?_toArray (p : α → Bool) (l : List α) :
l.toArray.findFinIdx? p = l.findFinIdx? p := by
rw [Array.findFinIdx?, findFinIdx?, findFinIdx?_loop_toArray]
simp
@[simp, grind =] theorem findIdx?_toArray (p : α → Bool) (l : List α) :
l.toArray.findIdx? p = l.findIdx? p := by
rw [Array.findIdx?_eq_map_findFinIdx?_val, findIdx?_eq_map_findFinIdx?_val]
simp [Array.size]
private theorem idxAuxOf_toArray [BEq α] (a : α) (l : List α) (j : Nat) (w : l' = l.drop j) (h) :
l.toArray.idxOfAux a j = findFinIdx?.go (fun x => x == a) l l' j h := by
unfold idxOfAux
unfold findFinIdx?.go
split <;> rename_i h'
· cases l' with
| nil =>
simp at h h'
omega
| cons b l' =>
simp at h'
have : l[j] = b := by
rw [drop_eq_getElem_cons h'] at w
simp only [cons.injEq] at w
exact w.1.symm
simp only [getElem_toArray, this]
split
· rfl
· simp only [length_cons] at h
have : l.length - (j + 1) < l.length - j := by omega
rw [idxAuxOf_toArray]
rw [drop_add_one_eq_tail_drop, ← w, tail_cons]
· have : l' = [] := by simp_all
subst this
simp
termination_by l.length - j
@[simp, grind =] theorem finIdxOf?_toArray [BEq α] (a : α) (l : List α) :
l.toArray.finIdxOf? a = l.finIdxOf? a := by
rw [Array.finIdxOf?, finIdxOf?, findFinIdx?]
simp [idxAuxOf_toArray]
@[simp, grind =] theorem idxOf?_toArray [BEq α] (a : α) (l : List α) :
l.toArray.idxOf? a = l.idxOf? a := by
rw [Array.idxOf?, idxOf?]
simp [finIdxOf?, findIdx?_eq_map_findFinIdx?_val, Array.size]
@[simp, grind =] theorem findIdx_toArray {as : List α} {p : α → Bool} :
as.toArray.findIdx p = as.findIdx p := by
rw [Array.findIdx, findIdx?_toArray, findIdx_eq_getD_findIdx?, Array.size]
@[simp, grind =] theorem idxOf_toArray [BEq α] {as : List α} {a : α} :
as.toArray.idxOf a = as.idxOf a := by
rw [Array.idxOf, findIdx_toArray, idxOf]
theorem isPrefixOfAux_toArray_succ [BEq α] (l₁ l₂ : List α) (hle : l₁.length ≤ l₂.length) (i : Nat) :
Array.isPrefixOfAux l₁.toArray l₂.toArray hle (i + 1) =
Array.isPrefixOfAux l₁.tail.toArray l₂.tail.toArray (by simp; omega) i := by
rw [Array.isPrefixOfAux]
conv => rhs; rw [Array.isPrefixOfAux]
simp only [size_toArray, getElem_toArray, Bool.if_false_right, length_tail, getElem_tail]
split <;> rename_i h₁ <;> split <;> rename_i h₂
· rw [isPrefixOfAux_toArray_succ]
· omega
· omega
· rfl
theorem isPrefixOfAux_toArray_succ' [BEq α] (l₁ l₂ : List α) (hle : l₁.length ≤ l₂.length) (i : Nat) :
Array.isPrefixOfAux l₁.toArray l₂.toArray hle (i + 1) =
Array.isPrefixOfAux (l₁.drop (i+1)).toArray (l₂.drop (i+1)).toArray (by simp; omega) 0 := by
induction i generalizing l₁ l₂ with
| zero => simp [isPrefixOfAux_toArray_succ]
| succ i ih =>
rw [isPrefixOfAux_toArray_succ, ih]
simp
theorem isPrefixOfAux_toArray_zero [BEq α] (l₁ l₂ : List α) (hle : l₁.length ≤ l₂.length) :
Array.isPrefixOfAux l₁.toArray l₂.toArray hle 0 =
l₁.isPrefixOf l₂ := by
rw [Array.isPrefixOfAux]
match l₁, l₂ with
| [], _ => rw [dif_neg] <;> simp
| _::_, [] => simp at hle
| a::l₁, b::l₂ =>
simp [isPrefixOf_cons₂, isPrefixOfAux_toArray_succ', isPrefixOfAux_toArray_zero]
@[simp, grind =] theorem isPrefixOf_toArray [BEq α] (l₁ l₂ : List α) :
l₁.toArray.isPrefixOf l₂.toArray = l₁.isPrefixOf l₂ := by
rw [Array.isPrefixOf]
split <;> rename_i h
· simp [isPrefixOfAux_toArray_zero]
· simp only [Bool.false_eq]
induction l₁ generalizing l₂ with
| nil => simp at h
| cons a l₁ ih =>
cases l₂ with
| nil => simp
| cons b l₂ =>
simp only [isPrefixOf_cons₂, Bool.and_eq_false_imp]
intro w
rw [ih]
simp_all
theorem zipWithMAux_toArray_succ {m : Type u → Type v} [Monad m] (as : List α) (bs : List β) (f : α → β → m γ) (i : Nat) (xs : Array γ) :
zipWithMAux as.toArray bs.toArray f (i + 1) xs = zipWithMAux as.tail.toArray bs.tail.toArray f i xs := by
rw [zipWithMAux]
conv => rhs; rw [zipWithMAux]
simp only [size_toArray, getElem_toArray, length_tail, getElem_tail]
split <;> rename_i h₁
· split <;> rename_i h₂
· rw [dif_pos (by omega), dif_pos (by omega)]
simp only [zipWithMAux_toArray_succ as bs f (i+1)]
· rw [dif_pos (by omega)]
rw [dif_neg (by omega)]
· rw [dif_neg (by omega)]
theorem zipWithMAux_toArray_succ' {m : Type u → Type v} [Monad m] (as : List α) (bs : List β) (f : α → β → m γ) (i : Nat) (xs : Array γ) :
zipWithMAux as.toArray bs.toArray f (i + 1) xs = zipWithMAux (as.drop (i+1)).toArray (bs.drop (i+1)).toArray f 0 xs := by
induction i generalizing as bs xs with
| zero => simp [zipWithMAux_toArray_succ]
| succ i ih =>
rw [zipWithMAux_toArray_succ, ih]
simp
theorem zipWithMAux_toArray_zero {m : Type u → Type v} [Monad m] [LawfulMonad m] (f : α → β → m γ) (as : List α) (bs : List β) (xs : Array γ) :
zipWithMAux as.toArray bs.toArray f 0 xs = do return xs ++ (← List.zipWithM f as bs).toArray := by
rw [Array.zipWithMAux]
match as, bs with
| [], _ => simp
| _, [] => simp
| a :: as, b :: bs =>
simp [zipWithMAux_toArray_succ', zipWithMAux_toArray_zero, push_append_toArray]
@[simp, grind =] theorem zipWith_toArray (as : List α) (bs : List β) (f : α → β → γ) :
Array.zipWith f as.toArray bs.toArray = (List.zipWith f as bs).toArray := by
rw [Array.zipWith]
simp [zipWithMAux_toArray_zero, ← zipWithM'_eq_zipWithM]
@[simp, grind =] theorem zip_toArray (as : List α) (bs : List β) :
Array.zip as.toArray bs.toArray = (List.zip as bs).toArray := by
simp [Array.zip, zipWith_toArray, zip]
private theorem zipWithAll_go_toArray (as : List α) (bs : List β) (f : Option α → Option β → γ) (i : Nat) (xs : Array γ) :
zipWithAll.go f as.toArray bs.toArray i xs = xs ++ (List.zipWithAll f (as.drop i) (bs.drop i)).toArray := by
unfold zipWithAll.go
split <;> rename_i h
· rw [zipWithAll_go_toArray]
simp at h
simp only [getElem?_toArray, push_append_toArray]
if ha : i < as.length then
if hb : i < bs.length then
rw [List.drop_eq_getElem_cons ha, List.drop_eq_getElem_cons hb]
simp only [ha, hb, getElem?_eq_getElem, zipWithAll_cons_cons]
else
simp only [Nat.not_lt] at hb
rw [List.drop_eq_getElem_cons ha]
rw [(drop_eq_nil_iff (l := bs)).mpr (by omega), (drop_eq_nil_iff (l := bs)).mpr (by omega)]
simp only [zipWithAll_nil, map_drop, map_cons]
rw [getElem?_eq_getElem ha]
rw [getElem?_eq_none hb]
else
if hb : i < bs.length then
simp only [Nat.not_lt] at ha
rw [List.drop_eq_getElem_cons hb]
rw [(drop_eq_nil_iff (l := as)).mpr (by omega), (drop_eq_nil_iff (l := as)).mpr (by omega)]
simp only [nil_zipWithAll, map_drop, map_cons]
rw [getElem?_eq_getElem hb]
rw [getElem?_eq_none ha]
else
omega
· simp only [size_toArray, Nat.not_lt] at h
rw [drop_eq_nil_of_le (by omega), drop_eq_nil_of_le (by omega)]
simp
termination_by max as.length bs.length - i
decreasing_by simp_wf; decreasing_trivial_pre_omega
@[simp, grind =] theorem zipWithAll_toArray (f : Option α → Option β → γ) (as : List α) (bs : List β) :
Array.zipWithAll f as.toArray bs.toArray = (List.zipWithAll f as bs).toArray := by
simp [Array.zipWithAll, zipWithAll_go_toArray]
@[simp, grind =] theorem zipWithM_toArray {m : Type u → Type v} [Monad m] [LawfulMonad m] (f : α → β → m γ) (as : List α) (bs : List β) :
Array.zipWithM f as.toArray bs.toArray = do return (← List.zipWithM f as bs).toArray := by
rw [Array.zipWithM]
simp [zipWithMAux_toArray_zero]
@[simp, grind =] theorem toArray_appendList (l₁ l₂ : List α) :
l₁.toArray ++ l₂ = (l₁ ++ l₂).toArray := by
apply ext'
simp
@[simp, grind =] theorem pop_toArray (l : List α) : l.toArray.pop = l.dropLast.toArray := by
apply ext'
simp
private theorem takeWhile_go_succ (p : α → Bool) (a : α) (l : List α) (i : Nat) :
takeWhile.go p (a :: l).toArray (i+1) r = takeWhile.go p l.toArray i r := by
rw [takeWhile.go, takeWhile.go]
simp only [size_toArray, length_cons, Nat.add_lt_add_iff_right,
getElem_toArray, getElem_cons_succ]
split
rw [takeWhile_go_succ]
rfl
private theorem takeWhile_go_toArray (p : α → Bool) (l : List α) (i : Nat) :
Array.takeWhile.go p l.toArray i r = r ++ (takeWhile p (l.drop i)).toArray := by
induction l generalizing i r with
| nil => simp [takeWhile.go]
| cons a l ih =>
rw [takeWhile.go]
cases i with
| zero =>
simp [takeWhile_go_succ, ih, takeWhile_cons]
split <;> simp
| succ i =>
simp only [size_toArray, length_cons, Nat.add_lt_add_iff_right,
getElem_toArray, getElem_cons_succ, drop_succ_cons]
split <;> rename_i h₁
· rw [takeWhile_go_succ, ih]
rw [← getElem_cons_drop_succ_eq_drop h₁, takeWhile_cons]
split <;> simp_all
· simp_all [drop_eq_nil_of_le]
@[simp, grind =] theorem takeWhile_toArray (p : α → Bool) (l : List α) :
l.toArray.takeWhile p = (l.takeWhile p).toArray := by
simp [Array.takeWhile, takeWhile_go_toArray]
private theorem popWhile_toArray_aux (p : α → Bool) (l : List α) :
l.reverse.toArray.popWhile p = (l.dropWhile p).reverse.toArray := by
induction l with
| nil => simp
| cons a l ih =>
unfold popWhile
simp [ih, dropWhile_cons]
split
· rfl
· simp
@[simp, grind =] theorem popWhile_toArray (p : α → Bool) (l : List α) :
l.toArray.popWhile p = (l.reverse.dropWhile p).reverse.toArray := by
simp [← popWhile_toArray_aux]
@[simp, grind =] theorem setIfInBounds_toArray (l : List α) (i : Nat) (a : α) :
l.toArray.setIfInBounds i a = (l.set i a).toArray := by
apply ext'
simp only [setIfInBounds]
split
· simp
· simp_all [List.set_eq_of_length_le]
@[simp, grind =] theorem toArray_replicate (n : Nat) (v : α) :
(List.replicate n v).toArray = Array.replicate n v := rfl
theorem _root_.Array.replicate_eq_toArray_replicate :
Array.replicate n v = (List.replicate n v).toArray := by
simp
@[simp, grind =] theorem flatMap_empty {β} (f : α → Array β) : (#[] : Array α).flatMap f = #[] := rfl
theorem flatMap_toArray_cons {β} (f : α → Array β) (a : α) (as : List α) :
(a :: as).toArray.flatMap f = f a ++ as.toArray.flatMap f := by
simp [Array.flatMap]
suffices ∀ xs, List.foldl (fun ys a => ys ++ f a) (f a ++ xs) as =
f a ++ List.foldl (fun ys a => ys ++ f a) xs as by
erw [empty_append] -- Why doesn't this work via `simp`?
simpa using this #[]
intro xs
induction as generalizing xs <;> simp_all
@[simp, grind =] theorem flatMap_toArray {β} (f : α → Array β) (as : List α) :
as.toArray.flatMap f = (as.flatMap (fun a => (f a).toList)).toArray := by
induction as with
| nil => simp
| cons a as ih =>
apply ext'
simp [ih, flatMap_toArray_cons]
@[simp, grind =] theorem swap_toArray (l : List α) (i j : Nat) {hi hj}:
l.toArray.swap i j hi hj = ((l.set i l[j]).set j l[i]).toArray := by
apply ext'
simp
@[simp, grind =] theorem eraseIdx_toArray (l : List α) (i : Nat) (h : i < l.toArray.size) :
l.toArray.eraseIdx i h = (l.eraseIdx i).toArray := by
rw [Array.eraseIdx]
split <;> rename_i h'
· rw [eraseIdx_toArray]
simp only [swap_toArray, toList_toArray, mk.injEq]
rw [eraseIdx_set_gt (by simp), eraseIdx_set_eq]
simp
· simp at h h'
have t : i = l.length - 1 := by omega
simp [t]
termination_by l.length - i
decreasing_by
rename_i h
simp at h
simp
omega
@[simp, grind =] theorem eraseIdxIfInBounds_toArray (l : List α) (i : Nat) :
l.toArray.eraseIdxIfInBounds i = (l.eraseIdx i).toArray := by
rw [Array.eraseIdxIfInBounds]
split
· simp
· simp_all [eraseIdx_eq_self.2]
@[simp, grind =] theorem eraseP_toArray {as : List α} {p : α → Bool} :
as.toArray.eraseP p = (as.eraseP p).toArray := by
rw [Array.eraseP, List.eraseP_eq_eraseIdx, findFinIdx?_toArray]
split <;> simp [*, findIdx?_eq_map_findFinIdx?_val]
@[simp, grind =] theorem erase_toArray [BEq α] {as : List α} {a : α} :
as.toArray.erase a = (as.erase a).toArray := by
rw [Array.erase, finIdxOf?_toArray, List.erase_eq_eraseIdx]
rw [idxOf?_eq_map_finIdxOf?_val]
split <;> simp_all
private theorem insertIdx_loop_toArray (i : Nat) (l : List α) (j : Nat) (hj : j < l.toArray.size) (h : i ≤ j) :
insertIdx.loop i l.toArray ⟨j, hj⟩ = (l.take i ++ l[j] :: (l.take j).drop i ++ l.drop (j + 1)).toArray := by
rw [insertIdx.loop]
simp only [size_toArray] at hj
split <;> rename_i h'
· simp only at h'
have w : j - 1 + 1 = j := by omega
simp only [append_assoc, cons_append]
rw [insertIdx_loop_toArray _ _ _ _ (by omega)]
simp only [swap_toArray, w, append_assoc, cons_append, mk.injEq]
rw [take_set_of_le (by omega), drop_eq_getElem_cons (i := j) (by simpa), getElem_set_self,
drop_set_of_lt (by omega), drop_set_of_lt (by omega), getElem_set_ne (by omega),
getElem_set_self, take_set_of_le (j := j - 1) (by omega),
take_set_of_le (j := j - 1) (by omega), take_eq_append_getElem_of_pos (by omega) hj,
drop_append_of_le_length (by simp; omega)]
simp only [append_assoc, cons_append, nil_append, append_cancel_right_eq]
cases i with
| zero => simp
| succ i => rw [take_set_of_le (by omega)]
· simp only [Nat.not_lt] at h'
have : i = j := by omega
subst this
simp
@[simp, grind =] theorem insertIdx_toArray (l : List α) (i : Nat) (a : α) (h : i ≤ l.toArray.size):
l.toArray.insertIdx i a = (l.insertIdx i a).toArray := by
rw [Array.insertIdx]
rw [insertIdx_loop_toArray (h := h)]
ext j h₁ h₂
· simp at h
simp [length_insertIdx, h]
omega
· simp [length_insertIdx] at h₁ h₂
simp [getElem_insertIdx]
split <;> rename_i h₃
· rw [getElem_append_left (by simp; split at h₂ <;> omega)]
simp only [getElem_take]
rw [getElem_append_left]
· rw [getElem_append_right (by simp; omega)]
rw [getElem_cons]
simp
split <;> rename_i h₄
· rw [dif_pos (by omega)]
· rw [dif_neg (by omega)]
congr
omega
@[simp, grind =] theorem insertIdxIfInBounds_toArray (l : List α) (i : Nat) (a : α) :
l.toArray.insertIdxIfInBounds i a = (l.insertIdx i a).toArray := by
rw [Array.insertIdxIfInBounds]
split <;> rename_i h'
· simp
· simp only [size_toArray, Nat.not_le] at h'
rw [List.insertIdx_of_length_lt (h := h')]
@[simp, grind =]
theorem replace_toArray [BEq α] [LawfulBEq α] (l : List α) (a b : α) :
l.toArray.replace a b = (l.replace a b).toArray := by
rw [Array.replace]
split <;> rename_i i h
· simp only [finIdxOf?_toArray] at h
rw [replace_of_not_mem]
exact finIdxOf?_eq_none_iff.mp h
· simp_all only [finIdxOf?_toArray, finIdxOf?_eq_some_iff, Fin.getElem_fin, set_toArray,
mk.injEq, Array.size]
apply List.ext_getElem
· simp
· intro j h₁ h₂
rw [List.getElem_replace, List.getElem_set]
by_cases h₃ : j < i
· rw [if_neg (by omega), if_neg]
simp only [length_set] at h₁ h₃
simpa using h.2 ⟨j, by omega⟩ h₃
· by_cases h₃ : j = i
· rw [if_pos (by omega), if_pos, if_neg]
· simp only [mem_take_iff_getElem, not_exists]
intro k hk
simpa using h.2 ⟨k, by omega⟩ (by change k < i.1; omega)
· subst h₃
simpa using h.1
· rw [if_neg (by omega)]
split
· rw [if_pos]
· simp_all
· simp only [mem_take_iff_getElem]
simp only [length_set] at h₁
exact ⟨i, by omega, h.1⟩
· rfl
@[simp, grind =] theorem leftpad_toArray (n : Nat) (a : α) (l : List α) :
Array.leftpad n a l.toArray = (leftpad n a l).toArray := by
simp [leftpad, Array.leftpad, ← toArray_replicate]
@[simp, grind =] theorem rightpad_toArray (n : Nat) (a : α) (l : List α) :
Array.rightpad n a l.toArray = (rightpad n a l).toArray := by
simp [rightpad, Array.rightpad, ← toArray_replicate]
end List