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3 Commits

Author SHA1 Message Date
Kim Morrison
8ccaaeefdc deprecation 2025-02-25 09:03:15 +11:00
Kim Morrison
3107edb098 Merge remote-tracking branch 'origin/master' into align_pop 2025-02-25 09:02:17 +11:00
Kim Morrison
0e7be2fb69 chore: align List.dropLast/Array.pop lemmas 2025-02-24 22:47:12 +11:00
2 changed files with 134 additions and 26 deletions

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@@ -3349,6 +3349,78 @@ theorem size_leftpad (n : Nat) (a : α) (xs : Array α) :
theorem size_rightpad (n : Nat) (a : α) (xs : Array α) :
(rightpad n a xs).size = max n xs.size := by simp; omega
/-! ### contains -/
theorem elem_cons_self [BEq α] [LawfulBEq α] {xs : Array α} {a : α} : (xs.push a).elem a = true := by simp
theorem contains_eq_any_beq [BEq α] (xs : Array α) (a : α) : xs.contains a = xs.any (a == ·) := by
rcases xs with xs
simp [List.contains_eq_any_beq]
theorem contains_iff_exists_mem_beq [BEq α] {xs : Array α} {a : α} :
xs.contains a a' xs, a == a' := by
rcases xs with xs
simp [List.contains_iff_exists_mem_beq]
theorem contains_iff_mem [BEq α] [LawfulBEq α] {xs : Array α} {a : α} :
xs.contains a a xs := by
simp
/-! ### more lemmas about `pop` -/
@[simp] theorem pop_empty : (#[] : Array α).pop = #[] := rfl
@[simp] theorem pop_push (xs : Array α) : (xs.push x).pop = xs := by simp [pop]
@[simp] theorem getElem_pop {xs : Array α} {i : Nat} (h : i < xs.pop.size) :
xs.pop[i] = xs[i]'(by simp at h; omega) := by
rcases xs with xs
simp [List.getElem_dropLast]
theorem getElem?_pop (xs : Array α) (i : Nat) :
xs.pop[i]? = if i < xs.size - 1 then xs[i]? else none := by
rcases xs with xs
simp [List.getElem?_dropLast]
theorem back_pop {xs : Array α} (h) :
xs.pop.back h =
xs[xs.size - 2]'(by simp at h; omega) := by
rcases xs with xs
simp [List.getLast_dropLast]
theorem back?_pop {xs : Array α} :
xs.pop.back? = if xs.size 1 then none else xs[xs.size - 2]? := by
rcases xs with xs
simp [List.getLast?_dropLast]
@[simp] theorem pop_append_of_ne_empty {xs : Array α} {ys : Array α} (h : ys #[]) :
(xs ++ ys).pop = xs ++ ys.pop := by
rcases xs with xs
rcases ys with ys
simp only [List.append_toArray, List.pop_toArray, mk.injEq]
rw [List.dropLast_append_of_ne_nil _ (by simpa using h)]
theorem pop_append {xs ys : Array α} :
(xs ++ ys).pop = if ys.isEmpty then xs.pop else xs ++ ys.pop := by
split <;> simp_all
@[simp] theorem pop_mkArray (n) (a : α) : (mkArray n a).pop = mkArray (n - 1) a := by
ext <;> simp
theorem eq_push_pop_back!_of_size_ne_zero [Inhabited α] {xs : Array α} (h : xs.size 0) :
xs = xs.pop.push xs.back! := by
apply ext
· simp [Nat.sub_add_cancel (Nat.zero_lt_of_ne_zero h)]
· intros i h h'
if hlt : i < xs.pop.size then
rw [getElem_push_lt (h:=hlt), getElem_pop]
else
have heq : i = xs.pop.size :=
Nat.le_antisymm (size_pop .. Nat.le_pred_of_lt h) (Nat.le_of_not_gt hlt)
cases heq
rw [getElem_push_eq, back!]
simp [ getElem!_pos]
/-! Content below this point has not yet been aligned with `List`. -/
/-! ### sum -/
@@ -3588,28 +3660,6 @@ theorem swapAt!_def (xs : Array α) (i : Nat) (v : α) (h : i < xs.size) :
· simp
· rfl
@[simp] theorem pop_empty : (#[] : Array α).pop = #[] := rfl
@[simp] theorem pop_push (xs : Array α) : (xs.push x).pop = xs := by simp [pop]
@[simp] theorem getElem_pop (xs : Array α) (i : Nat) (hi : i < xs.pop.size) :
xs.pop[i] = xs[i]'(Nat.lt_of_lt_of_le (xs.size_pop hi) (Nat.sub_le _ _)) :=
List.getElem_dropLast ..
theorem eq_push_pop_back!_of_size_ne_zero [Inhabited α] {xs : Array α} (h : xs.size 0) :
xs = xs.pop.push xs.back! := by
apply ext
· simp [Nat.sub_add_cancel (Nat.zero_lt_of_ne_zero h)]
· intros i h h'
if hlt : i < xs.pop.size then
rw [getElem_push_lt (h:=hlt), getElem_pop]
else
have heq : i = xs.pop.size :=
Nat.le_antisymm (size_pop .. Nat.le_pred_of_lt h) (Nat.le_of_not_gt hlt)
cases heq
rw [getElem_push_eq, back!]
simp [ getElem!_pos]
theorem eq_push_of_size_ne_zero {xs : Array α} (h : xs.size 0) :
(bs : Array α) (c : α), xs = bs.push c :=
let _ : Inhabited α := xs[0]

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@@ -2440,6 +2440,68 @@ theorem back?_mkVector (a : α) (n : Nat) :
(Vector.mk xs h).rightpad n a = Vector.mk (Array.rightpad n a xs) (by simp [h]; omega) := by
simp [h]
/-! ### contains -/
theorem contains_eq_any_beq [BEq α] (xs : Vector α n) (a : α) : xs.contains a = xs.any (a == ·) := by
rcases xs with xs, rfl
simp [Array.contains_eq_any_beq]
theorem contains_iff_exists_mem_beq [BEq α] {xs : Vector α n} {a : α} :
xs.contains a a' xs, a == a' := by
rcases xs with xs, rfl
simp [Array.contains_iff_exists_mem_beq]
theorem contains_iff_mem [BEq α] [LawfulBEq α] {xs : Vector α n} {a : α} :
xs.contains a a xs := by
simp
/-! ### more lemmas about `pop` -/
@[simp] theorem pop_empty : (#v[] : Vector α 0).pop = #v[] := rfl
@[simp] theorem pop_push (xs : Vector α n) : (xs.push x).pop = xs := by simp [pop]
@[simp] theorem getElem_pop {xs : Vector α n} {i : Nat} (h : i < n - 1) :
xs.pop[i] = xs[i] := by
rcases xs with xs, rfl
simp
theorem getElem?_pop (xs : Vector α n) (i : Nat) :
xs.pop[i]? = if i < n - 1 then xs[i]? else none := by
rcases xs with xs, rfl
simp [Array.getElem?_pop]
theorem back_pop {xs : Vector α n} [h : NeZero (n - 1)] :
xs.pop.back =
xs[n - 2]'(by have := h.out; omega) := by
rcases xs with xs, rfl
simp [Array.back_pop]
theorem back?_pop {xs : Vector α n} :
xs.pop.back? = if n 1 then none else xs[n - 2]? := by
rcases xs with xs, rfl
simp [Array.back?_pop]
@[simp] theorem pop_append_of_size_ne_zero {xs : Vector α n} {ys : Vector α m} (h : m 0) :
(xs ++ ys).pop = (xs ++ ys.pop).cast (by omega) := by
rcases xs with xs, rfl
rcases ys with ys, rfl
simp only [mk_append_mk, pop_mk, cast_mk, eq_mk]
rw [Array.pop_append_of_ne_empty]
apply Array.ne_empty_of_size_pos
omega
theorem pop_append {xs : Vector α n} {ys : Vector α m} :
(xs ++ ys).pop = if h : m = 0 then xs.pop.cast (by omega) else (xs ++ ys.pop).cast (by omega) := by
rcases xs with xs, rfl
rcases ys with ys, rfl
simp only [mk_append_mk, pop_mk, List.length_eq_zero_iff, Array.toList_eq_nil_iff, cast_mk, mk_eq]
rw [Array.pop_append]
split <;> simp_all
@[simp] theorem pop_mkVector (n) (a : α) : (mkVector n a).pop = mkVector (n - 1) a := by
ext <;> simp
/-! Content below this point has not yet been aligned with `List` and `Array`. -/
set_option linter.indexVariables false in
@@ -2447,10 +2509,6 @@ set_option linter.indexVariables false in
rcases xs with xs, rfl
simp
@[simp] theorem getElem_pop {xs : Vector α n} {i : Nat} (h : i < n - 1) : (xs.pop)[i] = xs[i] := by
rcases xs with xs, rfl
simp
/--
Variant of `getElem_pop` that will sometimes fire when `getElem_pop` gets stuck because of
defeq issues in the implicit size argument.