diff --git a/doc/lean/declarations.org b/doc/lean/declarations.org index 109388223..3c0421613 100644 --- a/doc/lean/declarations.org +++ b/doc/lean/declarations.org @@ -16,9 +16,9 @@ the expression =v = w= since it would not be able to establish that _definitionally equal_. #+BEGIN_SRC lean - import data.fixed_list data.nat + import data.tuple data.nat open nat - check λ (v : fixed_list nat (2+3)) (w : fixed_list nat 5), v = w + check λ (v : tuple nat (2+3)) (w : tuple nat 5), v = w #+END_SRC Similarly, the following definition only type checks because =id= is transparent, and the type checker can establish that diff --git a/library/data/examples/vector.lean b/library/data/examples/vector.lean index 7b3d95cd7..66ccfdf34 100644 --- a/library/data/examples/vector.lean +++ b/library/data/examples/vector.lean @@ -6,7 +6,7 @@ Author: Floris van Doorn, Leonardo de Moura This file demonstrates how to encode vectors using indexed inductive families. In standard library we do not use this approach. -/ -import data.nat data.list data.fin data.fixed_list +import data.nat data.list data.fin open nat prod fin inductive vector (A : Type) : nat → Type := diff --git a/library/data/fixed_list.lean b/library/data/tuple.lean similarity index 51% rename from library/data/fixed_list.lean rename to library/data/tuple.lean index 354da6e85..eb144f47d 100644 --- a/library/data/fixed_list.lean +++ b/library/data/tuple.lean @@ -3,51 +3,51 @@ Copyright (c) 2015 Microsoft Corporation. All rights reserved. Released under Apache 2.0 license as described in the file LICENSE. Author: Leonardo de Moura -The length of a list is encoded into its type. +Tuples are lists of a fixed size. It is implemented as a subtype. -/ import logic data.list data.fin open nat list subtype function -definition fixed_list [reducible] (A : Type) (n : nat) := {l : list A | length l = n} +definition tuple [reducible] (A : Type) (n : nat) := {l : list A | length l = n} -namespace fixed_list +namespace tuple variables {A B C : Type} - theorem induction_on [recursor 4] {P : ∀ {n}, fixed_list A n → Prop} - : ∀ {n} (v : fixed_list A n), (∀ (l : list A) {n : nat} (h : length l = n), P (tag l h)) → P v + theorem induction_on [recursor 4] {P : ∀ {n}, tuple A n → Prop} + : ∀ {n} (v : tuple A n), (∀ (l : list A) {n : nat} (h : length l = n), P (tag l h)) → P v | n (tag l h) H := @H l n h - definition nil : fixed_list A 0 := + definition nil : tuple A 0 := tag [] rfl lemma length_succ {n : nat} {l : list A} (a : A) : length l = n → length (a::l) = succ n := λ h, congr_arg succ h - definition cons {n : nat} : A → fixed_list A n → fixed_list A (succ n) + definition cons {n : nat} : A → tuple A n → tuple A (succ n) | a (tag v h) := tag (a::v) (length_succ a h) notation a :: b := cons a b - protected definition is_inhabited [instance] [h : inhabited A] : ∀ (n : nat), inhabited (fixed_list A n) + protected definition is_inhabited [instance] [h : inhabited A] : ∀ (n : nat), inhabited (tuple A n) | 0 := inhabited.mk nil | (succ n) := inhabited.mk (inhabited.value h :: inhabited.value (is_inhabited n)) - protected definition has_decidable_eq [instance] [h : decidable_eq A] : ∀ (n : nat), decidable_eq (fixed_list A n) := + protected definition has_decidable_eq [instance] [h : decidable_eq A] : ∀ (n : nat), decidable_eq (tuple A n) := _ - definition head {n : nat} : fixed_list A (succ n) → A + definition head {n : nat} : tuple A (succ n) → A | (tag [] h) := by contradiction | (tag (a::v) h) := a - definition tail {n : nat} : fixed_list A (succ n) → fixed_list A n + definition tail {n : nat} : tuple A (succ n) → tuple A n | (tag [] h) := by contradiction | (tag (a::v) h) := tag v (succ.inj h) - theorem head_cons {n : nat} (a : A) (v : fixed_list A n) : head (a :: v) = a := + theorem head_cons {n : nat} (a : A) (v : tuple A n) : head (a :: v) = a := by induction v; reflexivity - theorem tail_cons {n : nat} (a : A) (v : fixed_list A n) : tail (a :: v) = v := + theorem tail_cons {n : nat} (a : A) (v : tuple A n) : tail (a :: v) = v := by induction v; reflexivity theorem head_lcons {n : nat} (a : A) (l : list A) (h : length (a::l) = succ n) : head (tag (a::l) h) = a := @@ -56,19 +56,19 @@ namespace fixed_list theorem tail_lcons {n : nat} (a : A) (l : list A) (h : length (a::l) = succ n) : tail (tag (a::l) h) = tag l (succ.inj h) := rfl - definition last {n : nat} : fixed_list A (succ n) → A + definition last {n : nat} : tuple A (succ n) → A | (tag l h) := list.last l (ne_nil_of_length_eq_succ h) - theorem eta : ∀ {n : nat} (v : fixed_list A (succ n)), head v :: tail v = v + theorem eta : ∀ {n : nat} (v : tuple A (succ n)), head v :: tail v = v | 0 (tag [] h) := by contradiction | 0 (tag (a::l) h) := rfl | (n+1) (tag [] h) := by contradiction | (n+1) (tag (a::l) h) := rfl - definition of_list (l : list A) : fixed_list A (list.length l) := + definition of_list (l : list A) : tuple A (list.length l) := tag l rfl - definition to_list {n : nat} : fixed_list A n → list A + definition to_list {n : nat} : tuple A n → list A | (tag l h) := l theorem to_list_of_list (l : list A) : to_list (of_list l) = l := @@ -77,10 +77,10 @@ namespace fixed_list theorem to_list_nil : to_list nil = ([] : list A) := rfl - theorem length_to_list {n : nat} : ∀ (v : fixed_list A n), list.length (to_list v) = n + theorem length_to_list {n : nat} : ∀ (v : tuple A n), list.length (to_list v) = n | (tag l h) := h - theorem heq_of_list_eq {n m} : ∀ {v₁ : fixed_list A n} {v₂ : fixed_list A m}, to_list v₁ = to_list v₂ → n = m → v₁ == v₂ + theorem heq_of_list_eq {n m} : ∀ {v₁ : tuple A n} {v₂ : tuple A m}, to_list v₁ = to_list v₂ → n = m → v₁ == v₂ | (tag l₁ h₁) (tag l₂ h₂) e₁ e₂ := begin clear heq_of_list_eq, subst e₂, subst h₁, @@ -88,20 +88,20 @@ namespace fixed_list subst l₁ end - theorem list_eq_of_heq {n m} {v₁ : fixed_list A n} {v₂ : fixed_list A m} : v₁ == v₂ → n = m → to_list v₁ = to_list v₂ := + theorem list_eq_of_heq {n m} {v₁ : tuple A n} {v₂ : tuple A m} : v₁ == v₂ → n = m → to_list v₁ = to_list v₂ := begin intro h₁ h₂, revert v₁ v₂ h₁, subst n, intro v₁ v₂ h₁, rewrite [heq.to_eq h₁] end - theorem of_list_to_list {n : nat} (v : fixed_list A n) : of_list (to_list v) == v := + theorem of_list_to_list {n : nat} (v : tuple A n) : of_list (to_list v) == v := begin apply heq_of_list_eq, rewrite to_list_of_list, rewrite length_to_list end /- append -/ - definition append {n m : nat} : fixed_list A n → fixed_list A m → fixed_list A (n + m) + definition append {n m : nat} : tuple A n → tuple A m → tuple A (n + m) | (tag l₁ h₁) (tag l₂ h₂) := tag (list.append l₁ l₂) (by rewrite [length_append, h₁, h₂]) infix ++ := append @@ -111,40 +111,40 @@ namespace fixed_list lemma push_eq_rec : ∀ {n m : nat} {l : list A} (h₁ : n = m) (h₂ : length l = n), h₁ ▹ (tag l h₂) = tag l (h₁ ▹ h₂) | n n l (eq.refl n) h₂ := rfl - theorem append_nil_right {n : nat} (v : fixed_list A n) : v ++ nil = v := - induction_on v (λ l n h, by unfold [fixed_list.append, fixed_list.nil]; congruence; apply list.append_nil_right) + theorem append_nil_right {n : nat} (v : tuple A n) : v ++ nil = v := + induction_on v (λ l n h, by unfold [tuple.append, tuple.nil]; congruence; apply list.append_nil_right) - theorem append_nil_left {n : nat} (v : fixed_list A n) : !zero_add ▹ (nil ++ v) = v := - induction_on v (λ l n h, begin unfold [fixed_list.append, fixed_list.nil], rewrite [push_eq_rec] end) + theorem append_nil_left {n : nat} (v : tuple A n) : !zero_add ▹ (nil ++ v) = v := + induction_on v (λ l n h, begin unfold [tuple.append, tuple.nil], rewrite [push_eq_rec] end) - theorem append_nil_left_heq {n : nat} (v : fixed_list A n) : nil ++ v == v := + theorem append_nil_left_heq {n : nat} (v : tuple A n) : nil ++ v == v := heq_of_eq_rec_left !zero_add (append_nil_left v) - theorem append.assoc {n₁ n₂ n₃} : ∀ (v₁ : fixed_list A n₁) (v₂ : fixed_list A n₂) (v₃ : fixed_list A n₃), !add.assoc ▹ ((v₁ ++ v₂) ++ v₃) = v₁ ++ (v₂ ++ v₃) + theorem append.assoc {n₁ n₂ n₃} : ∀ (v₁ : tuple A n₁) (v₂ : tuple A n₂) (v₃ : tuple A n₃), !add.assoc ▹ ((v₁ ++ v₂) ++ v₃) = v₁ ++ (v₂ ++ v₃) | (tag l₁ h₁) (tag l₂ h₂) (tag l₃ h₃) := begin - unfold fixed_list.append, rewrite push_eq_rec, + unfold tuple.append, rewrite push_eq_rec, congruence, apply list.append.assoc end - theorem append.assoc_heq {n₁ n₂ n₃} (v₁ : fixed_list A n₁) (v₂ : fixed_list A n₂) (v₃ : fixed_list A n₃) : (v₁ ++ v₂) ++ v₃ == v₁ ++ (v₂ ++ v₃) := + theorem append.assoc_heq {n₁ n₂ n₃} (v₁ : tuple A n₁) (v₂ : tuple A n₂) (v₃ : tuple A n₃) : (v₁ ++ v₂) ++ v₃ == v₁ ++ (v₂ ++ v₃) := heq_of_eq_rec_left !add.assoc (append.assoc v₁ v₂ v₃) /- reverse -/ - definition reverse {n : nat} : fixed_list A n → fixed_list A n + definition reverse {n : nat} : tuple A n → tuple A n | (tag l h) := tag (list.reverse l) (by rewrite [length_reverse, h]) - theorem reverse_reverse {n : nat} (v : fixed_list A n) : reverse (reverse v) = v := + theorem reverse_reverse {n : nat} (v : tuple A n) : reverse (reverse v) = v := induction_on v (λ l n h, begin unfold reverse, congruence, apply list.reverse_reverse end) - theorem fixed_list0_eq_nil : ∀ (v : fixed_list A 0), v = nil + theorem tuple0_eq_nil : ∀ (v : tuple A 0), v = nil | (tag [] h) := rfl | (tag (a::l) h) := by contradiction /- mem -/ - definition mem {n : nat} (a : A) (v : fixed_list A n) : Prop := + definition mem {n : nat} (a : A) (v : tuple A n) : Prop := a ∈ elt_of v notation e ∈ s := mem e s @@ -153,101 +153,101 @@ namespace fixed_list theorem not_mem_nil (a : A) : a ∉ nil := list.not_mem_nil a - theorem mem_cons [simp] {n : nat} (a : A) (v : fixed_list A n) : a ∈ a :: v := + theorem mem_cons [simp] {n : nat} (a : A) (v : tuple A n) : a ∈ a :: v := induction_on v (λ l n h, !list.mem_cons) - theorem mem_cons_of_mem {n : nat} (y : A) {x : A} {v : fixed_list A n} : x ∈ v → x ∈ y :: v := + theorem mem_cons_of_mem {n : nat} (y : A) {x : A} {v : tuple A n} : x ∈ v → x ∈ y :: v := induction_on v (λ l n h₁ h₂, list.mem_cons_of_mem y h₂) - theorem eq_or_mem_of_mem_cons {n : nat} {x y : A} {v : fixed_list A n} : x ∈ y::v → x = y ∨ x ∈ v := + theorem eq_or_mem_of_mem_cons {n : nat} {x y : A} {v : tuple A n} : x ∈ y::v → x = y ∨ x ∈ v := induction_on v (λ l n h₁ h₂, eq_or_mem_of_mem_cons h₂) - theorem mem_singleton {n : nat} {x a : A} : x ∈ (a::nil : fixed_list A 1) → x = a := + theorem mem_singleton {n : nat} {x a : A} : x ∈ (a::nil : tuple A 1) → x = a := assume h, list.mem_singleton h /- map -/ - definition map {n : nat} (f : A → B) : fixed_list A n → fixed_list B n + definition map {n : nat} (f : A → B) : tuple A n → tuple B n | (tag l h) := tag (list.map f l) (by clear map; substvars; rewrite length_map) theorem map_nil (f : A → B) : map f nil = nil := rfl - theorem map_cons {n : nat} (f : A → B) (a : A) (v : fixed_list A n) : map f (a::v) = f a :: map f v := + theorem map_cons {n : nat} (f : A → B) (a : A) (v : tuple A n) : map f (a::v) = f a :: map f v := by induction v; reflexivity theorem map_tag {n : nat} (f : A → B) (l : list A) (h : length l = n) : map f (tag l h) = tag (list.map f l) (by substvars; rewrite length_map) := by reflexivity - theorem map_map {n : nat} (g : B → C) (f : A → B) (v : fixed_list A n) : map g (map f v) = map (g ∘ f) v := + theorem map_map {n : nat} (g : B → C) (f : A → B) (v : tuple A n) : map g (map f v) = map (g ∘ f) v := begin cases v, rewrite *map_tag, apply subtype.eq, apply list.map_map end - theorem map_id {n : nat} (v : fixed_list A n) : map id v = v := + theorem map_id {n : nat} (v : tuple A n) : map id v = v := begin induction v, unfold map, congruence, apply list.map_id end - theorem mem_map {n : nat} {a : A} {v : fixed_list A n} (f : A → B) : a ∈ v → f a ∈ map f v := + theorem mem_map {n : nat} {a : A} {v : tuple A n} (f : A → B) : a ∈ v → f a ∈ map f v := begin induction v, unfold map, apply list.mem_map end - theorem exists_of_mem_map {n : nat} {f : A → B} {b : B} {v : fixed_list A n} : b ∈ map f v → ∃a, a ∈ v ∧ f a = b := + theorem exists_of_mem_map {n : nat} {f : A → B} {b : B} {v : tuple A n} : b ∈ map f v → ∃a, a ∈ v ∧ f a = b := begin induction v, unfold map, apply list.exists_of_mem_map end - theorem eq_of_map_const {n : nat} {b₁ b₂ : B} {v : fixed_list A n} : b₁ ∈ map (const A b₂) v → b₁ = b₂ := + theorem eq_of_map_const {n : nat} {b₁ b₂ : B} {v : tuple A n} : b₁ ∈ map (const A b₂) v → b₁ = b₂ := begin induction v, unfold map, apply list.eq_of_map_const end /- product -/ - definition product {n m : nat} : fixed_list A n → fixed_list B m → fixed_list (A × B) (n * m) + definition product {n m : nat} : tuple A n → tuple B m → tuple (A × B) (n * m) | (tag l₁ h₁) (tag l₂ h₂) := tag (list.product l₁ l₂) (by rewrite [length_product, h₁, h₂]) - theorem nil_product {m : nat} (v : fixed_list B m) : !zero_mul ▹ product (@nil A) v = nil := + theorem nil_product {m : nat} (v : tuple B m) : !zero_mul ▹ product (@nil A) v = nil := begin induction v, unfold [nil, product], rewrite push_eq_rec end - theorem nil_product_heq {m : nat} (v : fixed_list B m) : product (@nil A) v == (@nil (A × B)) := + theorem nil_product_heq {m : nat} (v : tuple B m) : product (@nil A) v == (@nil (A × B)) := heq_of_eq_rec_left _ (nil_product v) - theorem product_nil {n : nat} (v : fixed_list A n) : product v (@nil B) = nil := + theorem product_nil {n : nat} (v : tuple A n) : product v (@nil B) = nil := begin induction v, unfold [nil, product], congruence, apply list.product_nil end - theorem mem_product {n m : nat} {a : A} {b : B} {v₁ : fixed_list A n} {v₂ : fixed_list B m} : a ∈ v₁ → b ∈ v₂ → (a, b) ∈ product v₁ v₂ := + theorem mem_product {n m : nat} {a : A} {b : B} {v₁ : tuple A n} {v₂ : tuple B m} : a ∈ v₁ → b ∈ v₂ → (a, b) ∈ product v₁ v₂ := begin cases v₁, cases v₂, unfold product, apply list.mem_product end - theorem mem_of_mem_product_left {n m : nat} {a : A} {b : B} {v₁ : fixed_list A n} {v₂ : fixed_list B m} : (a, b) ∈ product v₁ v₂ → a ∈ v₁ := + theorem mem_of_mem_product_left {n m : nat} {a : A} {b : B} {v₁ : tuple A n} {v₂ : tuple B m} : (a, b) ∈ product v₁ v₂ → a ∈ v₁ := begin cases v₁, cases v₂, unfold product, apply list.mem_of_mem_product_left end - theorem mem_of_mem_product_right {n m : nat} {a : A} {b : B} {v₁ : fixed_list A n} {v₂ : fixed_list B m} : (a, b) ∈ product v₁ v₂ → b ∈ v₂ := + theorem mem_of_mem_product_right {n m : nat} {a : A} {b : B} {v₁ : tuple A n} {v₂ : tuple B m} : (a, b) ∈ product v₁ v₂ → b ∈ v₂ := begin cases v₁, cases v₂, unfold product, apply list.mem_of_mem_product_right end /- ith -/ open fin - definition ith {n : nat} : fixed_list A n → fin n → A + definition ith {n : nat} : tuple A n → fin n → A | (tag l h₁) (mk i h₂) := list.ith l i (by rewrite h₁; exact h₂) - lemma ith_zero {n : nat} (a : A) (v : fixed_list A n) (h : 0 < succ n) : ith (a::v) (mk 0 h) = a := + lemma ith_zero {n : nat} (a : A) (v : tuple A n) (h : 0 < succ n) : ith (a::v) (mk 0 h) = a := by induction v; reflexivity - lemma ith_fin_zero {n : nat} (a : A) (v : fixed_list A n) : ith (a::v) (zero n) = a := + lemma ith_fin_zero {n : nat} (a : A) (v : tuple A n) : ith (a::v) (zero n) = a := by unfold zero; apply ith_zero - lemma ith_succ {n : nat} (a : A) (v : fixed_list A n) (i : nat) (h : succ i < succ n) + lemma ith_succ {n : nat} (a : A) (v : tuple A n) (i : nat) (h : succ i < succ n) : ith (a::v) (mk (succ i) h) = ith v (mk_pred i h) := by induction v; reflexivity - lemma ith_fin_succ {n : nat} (a : A) (v : fixed_list A n) (i : fin n) + lemma ith_fin_succ {n : nat} (a : A) (v : tuple A n) (i : fin n) : ith (a::v) (succ i) = ith v i := begin cases i, unfold fin.succ, rewrite ith_succ end - lemma ith_zero_eq_head {n : nat} (v : fixed_list A (nat.succ n)) : ith v (zero n) = head v := + lemma ith_zero_eq_head {n : nat} (v : tuple A (nat.succ n)) : ith v (zero n) = head v := by rewrite [-eta v, ith_fin_zero, head_cons] - lemma ith_succ_eq_ith_tail {n : nat} (v : fixed_list A (nat.succ n)) (i : fin n) : ith v (succ i) = ith (tail v) i := + lemma ith_succ_eq_ith_tail {n : nat} (v : tuple A (nat.succ n)) (i : fin n) : ith v (succ i) = ith (tail v) i := by rewrite [-eta v, ith_fin_succ, tail_cons] - protected lemma ext {n : nat} (v₁ v₂ : fixed_list A n) (h : ∀ i : fin n, ith v₁ i = ith v₂ i) : v₁ = v₂ := + protected lemma ext {n : nat} (v₁ v₂ : tuple A n) (h : ∀ i : fin n, ith v₁ i = ith v₂ i) : v₁ = v₂ := begin induction n with n ih, - rewrite [fixed_list0_eq_nil v₁, fixed_list0_eq_nil v₂], + rewrite [tuple0_eq_nil v₁, tuple0_eq_nil v₂], rewrite [-eta v₁, -eta v₂], congruence, show head v₁ = head v₂, by rewrite [-ith_zero_eq_head, -ith_zero_eq_head]; apply h, have ∀ i : fin n, ith (tail v₁) i = ith (tail v₂) i, from @@ -257,7 +257,7 @@ namespace fixed_list /- tabulate -/ - definition tabulate : Π {n : nat}, (fin n → A) → fixed_list A n + definition tabulate : Π {n : nat}, (fin n → A) → tuple A n | 0 f := nil | (n+1) f := f (@zero n) :: tabulate (λ i : fin n, f (succ i)) @@ -269,4 +269,4 @@ namespace fixed_list {unfold tabulate, rewrite ith_zero}, {unfold tabulate, rewrite [ith_succ, ih]} end -end fixed_list +end tuple