diff options
Diffstat (limited to '')
| -rw-r--r-- | tests/lean/Hashmap/Properties.lean | 116 |
1 files changed, 112 insertions, 4 deletions
diff --git a/tests/lean/Hashmap/Properties.lean b/tests/lean/Hashmap/Properties.lean index b2d5570a..92285c0d 100644 --- a/tests/lean/Hashmap/Properties.lean +++ b/tests/lean/Hashmap/Properties.lean @@ -55,6 +55,7 @@ theorem match_lawful_beq [BEq α] [LawfulBEq α] [DecidableEq α] (x y : α) : (x == y) = (if x = y then true else false) := by split <;> simp_all +@[pspec] theorem insert_in_list_spec0 {α : Type} (key: Usize) (value: α) (ls: List α) : ∃ b, insert_in_list α key value ls = ret b ∧ @@ -126,6 +127,10 @@ def hash_mod_key (k : Usize) (l : Int) : Int := | .ret k => k.val % l | _ => 0 +@[simp] +theorem hash_mod_key_eq : hash_mod_key k l = k.val % l := by + simp [hash_mod_key, hash_key] + def slot_s_inv_hash (l i : Int) (ls : Core.List (Usize × α)) : Prop := ls.allP (λ (k, _) => hash_mod_key k l = i) @@ -246,6 +251,7 @@ theorem insert_in_list_back_spec {α : Type} (l : Int) (key: Usize) (value: α) progress with insert_in_list_back_spec_aux as ⟨ l1 .. ⟩ exists l1 +@[simp] def slots_t_lookup (s : Core.List (List α)) (k : Usize) : Option α := let i := hash_mod_key k s.len let slot := s.index i @@ -260,7 +266,15 @@ abbrev len_s (hm : HashMap α) : Int := hm.al_v.len set_option trace.Progress true /-set_option pp.explicit true set_option pp.universes true -set_option pp.notation false-/ +set_option pp.notation false -/ + +-- Remark: α and β must live in the same universe, otherwise the +-- bind doesn't work +theorem if_update_eq + {α β : Type u} (b : Bool) (y : α) (e : Result α) (f : α → Result β) : + (if b then Bind.bind e f else f y) = Bind.bind (if b then e else pure y) f + := by + split <;> simp [Pure.pure] theorem insert_no_resize_spec {α : Type} (hm : HashMap α) (key : Usize) (value : α) (hinv : hm.inv) (hnsat : hm.lookup key = none → hm.len_s < Usize.max) : @@ -270,18 +284,112 @@ theorem insert_no_resize_spec {α : Type} (hm : HashMap α) (key : Usize) (value -- We updated the binding for key nhm.lookup key = some value ∧ -- We left the other bindings unchanged - (∀ k, k ≠ key → nhm.lookup k = hm.lookup k) ∧ + (∀ k, ¬ k = key → nhm.lookup k = hm.lookup k) ∧ -- Reasoning about the length (match hm.lookup key with | none => nhm.len_s = hm.len_s + 1 | some _ => nhm.len_s = hm.len_s) := by rw [insert_no_resize] simp [hash_key] - have : (Vec.len (List α) hm.slots).val ≠ 0 := by + have _ : (Vec.len (List α) hm.slots).val ≠ 0 := by checkpoint intro simp_all [inv] - progress as ⟨ hash_mod ⟩ + -- TODO: progress keep as ⟨ ... ⟩ : conflict + progress keep as h as ⟨ hash_mod, hhm ⟩ + have _ : 0 ≤ hash_mod.val := by checkpoint scalar_tac + have _ : hash_mod.val < Vec.length hm.slots := by sorry + -- have h := Primitives.Vec.index_mut_spec hm.slots hash_mod + -- TODO: change the spec of Vec.index_mut to introduce a let-binding. + -- or: make progress introduce the let-binding by itself (this is clearer) progress + -- TODO: make progress use the names written in the goal + progress as ⟨ inserted ⟩ + rw [if_update_eq] -- TODO: necessary because we don't have a join + -- TODO: progress to ... + have hipost : + ∃ i0, (if inserted = true then hm.num_entries + Usize.ofInt 1 else pure hm.num_entries) = ret i0 ∧ + i0.val = if inserted then hm.num_entries.val + 1 else hm.num_entries.val + := by sorry + progress as ⟨ i0 ⟩ + -- TODO: progress "eager" to match premises with assumptions while instantiating + -- meta-variables + have h_slot : slot_s_inv_hash hm.slots.length hash_mod.val (hm.slots.v.index hash_mod.val).v := by sorry + have hd : distinct_keys (hm.slots.v.index hash_mod.val).v := by checkpoint + simp [inv, slots_t_inv, slot_t_inv] at hinv + have h := hinv.right.left hash_mod.val (by assumption) (by assumption) + simp [h] + -- TODO: hide the variables and only keep the props + -- TODO: allow providing terms to progress to instantiate the meta variables + -- which are not propositions + progress as ⟨ l0, _, _, _, hlen .. ⟩ + . checkpoint exact hm.slots.length + . checkpoint simp_all + . -- Finishing the proof + progress as ⟨ v ⟩ + -- TODO: update progress to automate that + let nhm : HashMap α := { num_entries := i0, max_load_factor := hm.max_load_factor, max_load := hm.max_load, slots := v } + exists nhm + have hupdt : lookup nhm key = some value := by checkpoint + simp [lookup, List.lookup] at * + simp_all + have hlkp : ∀ k, ¬ k = key → nhm.lookup k = hm.lookup k := by checkpoint + simp [lookup, List.lookup] at * + intro k hk + -- We have to make a case disjunction: either the hashes are different, + -- in which case we don't even lookup the same slots, or the hashes + -- are the same, in which case we have to reason about what happens + -- in one slot + let k_hash_mod := k.val % v.val.len + have _ : 0 ≤ k_hash_mod := by sorry + have _ : k_hash_mod < Vec.length hm.slots := by sorry + if h_hm : k_hash_mod = hash_mod.val then + simp_all + else + simp_all + have _ : + match hm.lookup key with + | none => nhm.len_s = hm.len_s + 1 + | some _ => nhm.len_s = hm.len_s := by checkpoint + simp only [lookup, List.lookup, len_s, al_v, HashMap.v, slots_t_lookup] at * + -- We have to do a case disjunction + simp_all + simp [_root_.List.update_map_eq] + -- TODO: dependent rewrites + have _ : key.val % hm.slots.val.len < (List.map List.v hm.slots.val).len := by + simp [*] + simp [_root_.List.len_flatten_update_eq, *] + split <;> + rename_i heq <;> + simp [heq] at hlen <;> + -- TODO: canonize addition by default? We need a tactic to simplify arithmetic equalities + -- with addition and substractions ((ℤ, +) is a ring or something - there should exist a tactic + -- somewhere in mathlib?) + simp [Int.add_assoc, Int.add_comm, Int.add_left_comm] <;> + int_tac + have hinv : inv nhm := by + simp [inv] at * + split_conjs + . match h: lookup hm key with + | none => + simp [h, lookup] at * + simp_all + | some _ => + simp_all [lookup] + . simp [slots_t_inv, slot_t_inv] at * + intro i hipos _ + have hs := hinv.right.left i hipos (by simp_all) + -- We need a case disjunction + if i = key.val % _root_.List.len hm.slots.val then + simp_all + else + simp_all + . match h: lookup hm key with + | none => + simp [h] at * + simp [*] + | some _ => + simp_all + simp_all end HashMap |