Files
agda-spa/lean/Spa/Analysis/Sign.lean

412 lines
14 KiB
Lean4
Raw Normal View History

/-
Port of `Analysis/Sign.agda`.
Correspondence:
Sign (+ / - / 0ˢ) Sign.plus / Sign.minus / Sign.zero
__, -equiv, -Decidable deriving DecidableEq
SignLattice (AboveBelow) SignLattice
AB.Plain 0ˢ signFixedHeight (AboveBelow.plainFixedHeight .zero)
plus, minus plus, minus
plus-Monoˡ/ʳ, minus-Monoˡ/ʳ (postulates in Agda!)
plus_mono_left/right, minus_mono_left/right
now actually proved, via AboveBelow.le_cases
plus-Mono₂, minus-Mono₂ plus_mono₂, minus_mono₂
_ interpSign
-respects- (trivial with `=`)
--, -- interpSign_sup, interpSign_inf
s₁s₂¬s₁s₂ interpSign_mk_disjoint
latticeInterpretation signInterpretation
WithProg.eval, eval-Monoʳ SignAnalysis.eval, eval_mono
SignEval (instance) SignAnalysis.exprEvaluator
plus-valid, minus-valid plus_valid, minus_valid
eval-valid, SignEvalValid eval_valid
output SignAnalysis.output
analyze-correct SignAnalysis.analyze_correct
-/
import Spa.Analysis.Forward
import Spa.Analysis.Utils
import Spa.Showable
namespace Spa
inductive Sign where
| plus
| minus
| zero
deriving DecidableEq
instance : Showable Sign :=
fun
| .plus => "+"
| .minus => "-"
| .zero => "0"
/-- Agda: the module parameter `x = 0ˢ` of `AB.Plain`. -/
instance : Inhabited Sign := .zero
abbrev SignLattice : Type := AboveBelow Sign
/-- Agda: `AB.Plain 0ˢ`'s `fixedHeight`. -/
def signFixedHeight : FixedHeight SignLattice 2 :=
AboveBelow.plainFixedHeight Sign.zero
open AboveBelow in
/-- Agda: `plus`. -/
def plus : SignLattice SignLattice SignLattice
| bot, _ => bot
| _, bot => bot
| top, _ => top
| _, top => top
| mk .plus, mk .plus => mk .plus
| mk .plus, mk .minus => top
| mk .plus, mk .zero => mk .plus
| mk .minus, mk .plus => top
| mk .minus, mk .minus => mk .minus
| mk .minus, mk .zero => mk .minus
| mk .zero, mk .plus => mk .plus
| mk .zero, mk .minus => mk .minus
| mk .zero, mk .zero => mk .zero
open AboveBelow in
/-- Agda: `minus`. -/
def minus : SignLattice SignLattice SignLattice
| bot, _ => bot
| _, bot => bot
| top, _ => top
| _, top => top
| mk .plus, mk .plus => top
| mk .plus, mk .minus => mk .plus
| mk .plus, mk .zero => mk .plus
| mk .minus, mk .plus => mk .minus
| mk .minus, mk .minus => top
| mk .minus, mk .zero => mk .minus
| mk .zero, mk .plus => mk .minus
| mk .zero, mk .minus => mk .plus
| mk .zero, mk .zero => mk .zero
/-- Agda: `plus-Monoˡ` — a postulate there, a theorem here. -/
theorem plus_mono_left (s₂ : SignLattice) : Monotone (plus · s₂) := by
intro a b h
rcases AboveBelow.le_cases h with rfl | rfl | rfl
· rcases s₂ with _ | _ | y <;> rcases b with _ | _ | x <;>
simp only [plus] <;>
first
| exact le_refl _
| exact AboveBelow.le_top' _
| exact AboveBelow.bot_le' _
· rcases s₂ with _ | _ | y <;> rcases a with _ | _ | x <;>
simp only [plus] <;>
first
| exact le_refl _
| exact AboveBelow.le_top' _
· exact le_refl _
/-- Agda: `plus-Monoʳ` — a postulate there, a theorem here. -/
theorem plus_mono_right (s₁ : SignLattice) : Monotone (plus s₁) := by
intro a b h
rcases AboveBelow.le_cases h with rfl | rfl | rfl
· rcases s₁ with _ | _ | x <;> rcases b with _ | _ | y <;>
simp only [plus] <;>
first
| exact le_refl _
| exact AboveBelow.le_top' _
| exact AboveBelow.bot_le' _
· rcases s₁ with _ | _ | x <;> rcases a with _ | _ | y <;>
simp only [plus] <;>
first
| exact le_refl _
| exact AboveBelow.le_top' _
· exact le_refl _
/-- Agda: `plus-Mono₂`. -/
theorem plus_mono₂ : Monotone₂ plus :=
plus_mono_left, plus_mono_right
/-- Agda: `minus-Monoˡ` — a postulate there, a theorem here. -/
theorem minus_mono_left (s₂ : SignLattice) : Monotone (minus · s₂) := by
intro a b h
rcases AboveBelow.le_cases h with rfl | rfl | rfl
· rcases s₂ with _ | _ | y <;> rcases b with _ | _ | x <;>
simp only [minus] <;>
first
| exact le_refl _
| exact AboveBelow.le_top' _
| exact AboveBelow.bot_le' _
· rcases s₂ with _ | _ | y <;> rcases a with _ | _ | x <;>
simp only [minus] <;>
first
| exact le_refl _
| exact AboveBelow.le_top' _
· exact le_refl _
/-- Agda: `minus-Monoʳ` — a postulate there, a theorem here. -/
theorem minus_mono_right (s₁ : SignLattice) : Monotone (minus s₁) := by
intro a b h
rcases AboveBelow.le_cases h with rfl | rfl | rfl
· rcases s₁ with _ | _ | x <;> rcases b with _ | _ | y <;>
simp only [minus] <;>
first
| exact le_refl _
| exact AboveBelow.le_top' _
| exact AboveBelow.bot_le' _
· rcases s₁ with _ | _ | x <;> rcases a with _ | _ | y <;>
simp only [minus] <;>
first
| exact le_refl _
| exact AboveBelow.le_top' _
· exact le_refl _
/-- Agda: `minus-Mono₂`. -/
theorem minus_mono₂ : Monotone₂ minus :=
minus_mono_left, minus_mono_right
/-- Agda: `⟦_⟧ᵍ`. -/
def interpSign : SignLattice Value Prop
| .bot, _ => False
| .top, _ => True
| .mk .plus, v => n : , v = .int (n + 1)
| .mk .zero, v => v = .int 0
| .mk .minus, v => n : , v = .int (-(n + 1))
/-- Agda: `s₁≢s₂⇒¬s₁∧s₂`. -/
theorem interpSign_mk_disjoint {s₁ s₂ : Sign} (hne : s₁ s₂) {v : Value} :
¬(interpSign (.mk s₁) v interpSign (.mk s₂) v) := by
rintro h₁, h₂
rcases s₁ <;> rcases s₂ <;> try exact hne rfl
all_goals simp only [interpSign] at h₁ h₂
· obtain n₁, rfl := h₁
obtain n₂, hv := h₂
injection hv with hz
omega
· obtain n₁, rfl := h₁
injection h₂ with hz
omega
· obtain n₁, rfl := h₁
obtain n₂, hv := h₂
injection hv with hz
omega
· obtain n₁, rfl := h₁
injection h₂ with hz
omega
· subst h₁
obtain n₂, hv := h₂
injection hv with hz
omega
· subst h₁
obtain n₂, hv := h₂
injection hv with hz
omega
/-- Agda: `⟦⟧ᵍ-⊔ᵍ-`. -/
theorem interpSign_sup {s₁ s₂ : SignLattice} (v : Value)
(h : interpSign s₁ v interpSign s₂ v) : interpSign (s₁ s₂) v := by
rcases s₁ with _ | _ | x
· rcases h with h | h
· exact h.elim
· rw [AboveBelow.bot_sup]
exact h
· exact trivial
· rcases s₂ with _ | _ | y
· rcases h with h | h
· rw [AboveBelow.sup_bot]
exact h
· exact h.elim
· rw [AboveBelow.sup_top]
exact trivial
· by_cases hxy : x = y
· subst hxy
rw [AboveBelow.mk_sup_mk, if_pos rfl]
rcases h with h | h <;> exact h
· rw [AboveBelow.mk_sup_mk, if_neg hxy]
exact trivial
/-- Agda: `⟦⟧ᵍ-⊓ᵍ-∧`. -/
theorem interpSign_inf {s₁ s₂ : SignLattice} (v : Value)
(h : interpSign s₁ v interpSign s₂ v) : interpSign (s₁ s₂) v := by
rcases s₁ with _ | _ | x
· exact h.1
· rw [AboveBelow.top_inf]
exact h.2
· rcases s₂ with _ | _ | y
· exact h.2
· rw [AboveBelow.inf_top]
exact h.1
· by_cases hxy : x = y
· subst hxy
rw [AboveBelow.mk_inf_mk, if_pos rfl]
exact h.1
· exact absurd h (interpSign_mk_disjoint hxy)
/-- Agda: `latticeInterpretationᵍ`. -/
def signInterpretation : LatticeInterpretation SignLattice where
interp := interpSign
interp_sup := fun {l₁ l₂} v h => interpSign_sup (s₁ := l₁) (s₂ := l₂) v h
interp_inf := fun {l₁ l₂} v h => interpSign_inf (s₁ := l₁) (s₂ := l₂) v h
namespace SignAnalysis
/-! Agda: `module WithProg (prog : Program)`. -/
variable (prog : Program)
/-- Agda: `WithProg.eval`. -/
def eval : Expr VariableValues SignLattice prog SignLattice
| .add e₁ e₂, vs => plus (eval e₁ vs) (eval e₂ vs)
| .sub e₁ e₂, vs => minus (eval e₁ vs) (eval e₂ vs)
| .var k, vs =>
if h : FiniteMap.MemKey k vs then (FiniteMap.locate h).1 else .top
| .num 0, _ => .mk .zero
| .num (_ + 1), _ => .mk .plus
/-- Agda: `WithProg.eval-Monoʳ`. -/
theorem eval_mono (e : Expr) : Monotone (eval prog e) := by
induction e with
| add e₁ e₂ ih₁ ih₂ =>
intro vs₁ vs₂ h
exact eval_combine₂ plus_mono₂ (ih₁ h) (ih₂ h)
| sub e₁ e₂ ih₁ ih₂ =>
intro vs₁ vs₂ h
exact eval_combine₂ minus_mono₂ (ih₁ h) (ih₂ h)
| var k =>
intro vs₁ vs₂ h
simp only [eval]
by_cases hk : k prog.vars
· rw [dif_pos (FiniteMap.memKey_iff.mpr hk),
dif_pos (FiniteMap.memKey_iff.mpr hk)]
exact FiniteMap.le_of_mem_mem prog.vars_nodup h
(FiniteMap.locate _).2 (FiniteMap.locate _).2
· rw [dif_neg (fun hm => hk (FiniteMap.memKey_iff.mp hm)),
dif_neg (fun hm => hk (FiniteMap.memKey_iff.mp hm))]
| num n =>
intro vs₁ vs₂ _
cases n <;> exact le_refl _
/-- Agda: the `SignEval` instance. -/
def exprEvaluator : ExprEvaluator SignLattice prog :=
eval prog, eval_mono prog
/-- Agda: `WithProg.result`/`output` — the analysis result, printed. -/
def output : String :=
show' (result signFixedHeight (exprEvaluator prog).toStmtEvaluator)
/-- Agda: `plus-valid`. -/
theorem plus_valid {g₁ g₂ : SignLattice} {z₁ z₂ : }
(h₁ : interpSign g₁ (.int z₁)) (h₂ : interpSign g₂ (.int z₂)) :
interpSign (plus g₁ g₂) (.int (z₁ + z₂)) := by
rcases g₁ with _ | _ | s₁
· exact h₁.elim
· rcases g₂ with _ | _ | s₂
· exact h₂.elim
· exact trivial
· exact trivial
· rcases g₂ with _ | _ | s₂
· exact h₂.elim
· rcases s₁ <;> exact trivial
· rcases s₁ <;> rcases s₂ <;>
simp only [plus, interpSign, Value.int.injEq] at h₁ h₂ <;>
try trivial
· obtain n₁, rfl := h₁
obtain n₂, rfl := h₂
exact n₁ + n₂ + 1, by omega
· obtain n₁, rfl := h₁
subst h₂
exact n₁, by omega
· obtain n₁, rfl := h₁
obtain n₂, rfl := h₂
exact n₁ + n₂ + 1, by omega
· obtain n₁, rfl := h₁
subst h₂
exact n₁, by omega
· subst h₁
obtain n₂, rfl := h₂
exact n₂, by omega
· subst h₁
obtain n₂, rfl := h₂
exact n₂, by omega
· subst h₁
subst h₂
omega
/-- Agda: `minus-valid`. -/
theorem minus_valid {g₁ g₂ : SignLattice} {z₁ z₂ : }
(h₁ : interpSign g₁ (.int z₁)) (h₂ : interpSign g₂ (.int z₂)) :
interpSign (minus g₁ g₂) (.int (z₁ - z₂)) := by
rcases g₁ with _ | _ | s₁
· exact h₁.elim
· rcases g₂ with _ | _ | s₂
· exact h₂.elim
· exact trivial
· exact trivial
· rcases g₂ with _ | _ | s₂
· exact h₂.elim
· rcases s₁ <;> exact trivial
· rcases s₁ <;> rcases s₂ <;>
simp only [minus, interpSign, Value.int.injEq] at h₁ h₂ <;>
try trivial
· obtain n₁, rfl := h₁
obtain n₂, rfl := h₂
exact n₁ + n₂ + 1, by omega
· obtain n₁, rfl := h₁
subst h₂
exact n₁, by omega
· obtain n₁, rfl := h₁
obtain n₂, rfl := h₂
exact n₁ + n₂ + 1, by omega
· obtain n₁, rfl := h₁
subst h₂
exact n₁, by omega
· subst h₁
obtain n₂, rfl := h₂
exact n₂, by omega
· subst h₁
obtain n₂, rfl := h₂
exact n₂, by omega
· subst h₁
subst h₂
omega
/-- Agda: `eval-valid` / `SignEvalValid`. -/
theorem eval_valid :
IsValidExprEvaluator (exprEvaluator prog) signInterpretation := by
intro vs ρ e v hev
induction hev with
| num n =>
intro _
show interpSign (eval prog (.num n) vs) (.int n)
cases n with
| zero => rfl
| succ n' => exact n', congrArg Value.int (by push_cast; ring)
| var x v hxv =>
intro hvs
show interpSign (eval prog (.var x) vs) v
simp only [eval]
by_cases hk : FiniteMap.MemKey x vs
· rw [dif_pos hk]
exact hvs _ _ (FiniteMap.locate hk).2 _ hxv
· rw [dif_neg hk]
exact trivial
| add e₁ e₂ z₁ z₂ _ _ ih₁ ih₂ =>
intro hvs
have h₁ : interpSign (eval prog e₁ vs) (.int z₁) := ih₁ hvs
have h₂ : interpSign (eval prog e₂ vs) (.int z₂) := ih₂ hvs
show interpSign (eval prog (.add e₁ e₂) vs) (.int (z₁ + z₂))
exact plus_valid h₁ h₂
| sub e₁ e₂ z₁ z₂ _ _ ih₁ ih₂ =>
intro hvs
have h₁ : interpSign (eval prog e₁ vs) (.int z₁) := ih₁ hvs
have h₂ : interpSign (eval prog e₂ vs) (.int z₂) := ih₂ hvs
show interpSign (eval prog (.sub e₁ e₂) vs) (.int (z₁ - z₂))
exact minus_valid h₁ h₂
/-- Agda: `WithProg.analyze-correct`. -/
theorem analyze_correct {ρ : Env} (hrun : EvalStmt [] prog.rootStmt ρ) :
interpV signInterpretation
(variablesAt prog.finalState
(result signFixedHeight (exprEvaluator prog).toStmtEvaluator)) ρ :=
Spa.analyze_correct signFixedHeight
((exprEvaluator prog).toStmtEvaluator_valid (eval_valid prog)) hrun
end SignAnalysis
end Spa