diff options
Diffstat (limited to 'backends')
| -rw-r--r-- | backends/lean/Base/Diverge/Base.lean | 29 |
1 files changed, 18 insertions, 11 deletions
diff --git a/backends/lean/Base/Diverge/Base.lean b/backends/lean/Base/Diverge/Base.lean index 89365d25..a8503107 100644 --- a/backends/lean/Base/Diverge/Base.lean +++ b/backends/lean/Base/Diverge/Base.lean @@ -57,6 +57,12 @@ deriving Repr, BEq open Result +instance Result_Inhabited (α : Type u) : Inhabited (Result α) := + Inhabited.mk (fail panic) + +instance Result_Nonempty (α : Type u) : Nonempty (Result α) := + Nonempty.intro div + def bind {α : Type u} {β : Type v} (x: Result α) (f: α -> Result β) : Result β := match x with | ret v => f v @@ -156,7 +162,14 @@ namespace Fix (x : a) (n : Nat) : Prop := fix_fuel_pred f x n - noncomputable + partial + def fixImpl (f : ((x:a) → Result (b x)) → (x:a) → Result (b x)) (x : a) : Result (b x) := + f (fixImpl f) x + + -- The fact that `fix` is implemented by `fixImpl` allows us to not mark the + -- functions defined with the fixed-point as noncomputable. One big advantage + -- is that it allows us to evaluate those functions, for instance with #eval. + @[implemented_by fixImpl] def fix (f : ((x:a) → Result (b x)) → (x:a) → Result (b x)) (x : a) : Result (b x) := fix_fuel (least (fix_fuel_P f x)) f x @@ -548,7 +561,7 @@ namespace FixI def is_valid (f : ((i:id) → (x:a i) → Result (b i x)) → (i:id) → (x:a i) → Result (b i x)) : Prop := ∀ k i x, is_valid_p k (λ k => f k i x) - noncomputable def fix + def fix (f : ((i:id) → (x:a i) → Result (b i x)) → (i:id) → (x:a i) → Result (b i x)) : (i:id) → (x:a i) → Result (b i x) := kk_of_gen (Fix.fix (k_to_gen f)) @@ -808,7 +821,6 @@ namespace Ex1 split <;> simp split <;> simp - noncomputable def list_nth (ls : List a) (i : Int) : Result a := fix list_nth_body (ls, i) -- The unfolding equation - diverges if `i < 0` @@ -851,7 +863,6 @@ namespace Ex2 split <;> simp apply is_valid_p_bind <;> intros <;> simp_all - noncomputable def list_nth (ls : List a) (i : Int) : Result a := fix list_nth_body (ls, i) -- The unfolding equation - diverges if `i < 0` @@ -932,7 +943,6 @@ namespace Ex3 apply is_valid_p_bind; simp intros; split <;> simp - noncomputable def is_even (i : Int): Result Bool := do let r ← fix is_even_is_odd_body (.inl i) @@ -940,7 +950,6 @@ namespace Ex3 | .inl b => .ret b | .inr _ => .fail .panic - noncomputable def is_odd (i : Int): Result Bool := do let r ← fix is_even_is_odd_body (.inr i) @@ -1032,8 +1041,8 @@ namespace Ex4 theorem body_fix_eq : fix body = body (fix body) := is_valid_fix_fixed_eq body_is_valid - noncomputable def is_even (i : Int) : Result Bool := fix body 0 i - noncomputable def is_odd (i : Int) : Result Bool := fix body 1 i + def is_even (i : Int) : Result Bool := fix body 0 i + def is_odd (i : Int) : Result Bool := fix body 1 i theorem is_even_eq (i : Int) : is_even i = (if i = 0 @@ -1052,7 +1061,6 @@ namespace Ex4 .ret b) := by simp [is_even, is_odd]; conv => lhs; rw [body_fix_eq] - end Ex4 namespace Ex5 @@ -1109,7 +1117,7 @@ namespace Ex5 intro k x simp only [is_valid_p_same, is_valid_p_rec] - noncomputable def id (t : Tree a) := fix id_body t + def id (t : Tree a) := fix id_body t -- The unfolding equation theorem id_eq (t : Tree a) : @@ -1183,7 +1191,6 @@ namespace Ex6 Funs.is_valid_p_is_valid_p tys k bodies (And.intro (list_nth_body_is_valid' k) (Funs.is_valid_p_Nil k)) - noncomputable def list_nth {a: Type u} (ls : List a) (i : Int) : Result a := fix body 0 ⟨ a, ls , i ⟩ |