implicitt/lib/Convert.ml
2022-08-31 20:49:40 +02:00

53 lines
2.0 KiB
OCaml

module V = Value
module E = Eval
exception Unequal (* todo, better exception *)
let rec conv_tp (len : int) (v1 : V.value) (v2 : V.value) =
match v1, v2 with
| Type, Type -> ()
| T0, T0 -> ()
| T1, T1 -> ()
| TNat, TNat -> ()
| TBool, TBool -> ()
| Pi (a1, C (env1, b1)), Pi (a2, C (env2, b2)) (* fallthrough *)
| Sg (a1, C (env1, b1)), Sg (a2, C (env2, b2)) ->
conv_tp len a1 a2;
let fresh = V.Stuck (V.Var (V.Lvl len), a1) in
conv_tp (len+1) (E.eval (fresh :: env1) b1) (E.eval (fresh :: env2) b2)
| Stuck (s1, Type), Stuck (s2, Type) -> conv_stuck len s1 s2
| _ -> raise Unequal
and conv_tr (len : int) (ty : V.value) (v1 : V.value) (v2 : V.value) =
match ty with
| Type -> conv_tp len v1 v2
| T1 -> () (* unit η-law, this still requires evaluation :/ *)
| Pi (a, C (env, b)) ->
let fresh = V.Stuck (V.Var (V.Lvl len), a) in
conv_tr (len+1) (E.eval (fresh :: env) b) (E.app v1 a) (E.app v2 a)
| Sg (a, C (env, b)) ->
let f1 = E.fst v1 in
conv_tr len a f1 (E.fst v2);
conv_tr len (E.eval (f1 :: env) b) (E.snd v1) (E.snd v2)
| _ ->
begin match v1, v2 with
| Zero, Zero -> ()
| Suc n, Suc m -> conv_tr len ty n m
| True, True -> ()
| False, False -> ()
| Stuck (s1, _), Stuck (s2, _) -> conv_stuck len s1 s2
| _ -> raise Unequal
end
and conv_stuck (len : int) (s1 : V.stuck) (s2 : V.stuck) =
match s1, s2 with
| Var (Lvl i), Var (Lvl j) -> if i == j then () else raise Unequal
| Fst p1, Fst p2 -> conv_stuck len p1 p2
| Snd p1, Snd p2 -> conv_stuck len p1 p2
| App (f1, x1, ty1), App (f2, x2, ty2) -> begin
conv_stuck len f1 f2;
conv_tp len ty1 ty2;
conv_tr len ty1 x1 x2
end
| _ -> raise Unequal