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Diffstat (limited to 'lib/Elab.ml')
| -rw-r--r-- | lib/Elab.ml | 161 |
1 files changed, 0 insertions, 161 deletions
diff --git a/lib/Elab.ml b/lib/Elab.ml deleted file mode 100644 index d911b9f..0000000 --- a/lib/Elab.ml +++ /dev/null @@ -1,161 +0,0 @@ -open Bwd -open Bwd.Infix - -module A = Ast -module S = Syntax -module D = Domain - -(* TODO: REALLY improve error messages *) - -(* invariant: `tps`, `tms` and `names` all have length `size` *) -type env = { - tps : D.env; - tms : D.env; - names : Ident.local bwd; - size : int; -} - -module Eff = Algaeff.Reader.Make (struct type nonrec t = env end) - -(** General helpers *) - -let lookup (id : Ident.t) : D.t * S.t = match Ident.to_local id with - | Some name -> begin - let env = Eff.read() in - match Bwd.find_index ((=) name) env.names with - | Some ix -> - let tp = Bwd.nth env.tps ix in - (tp, S.Var ix) - | None -> Reporter.unbound_variable id - end - | None -> Reporter.unbound_variable id - -let bind ~(name : Ident.local) ~(tp : D.t) f = - let arg = D.var (Eff.read()).size in - let update env = { - tps = env.tps <: tp; - tms = env.tms <: arg; - names = env.names <: name; - size = env.size + 1; - } in - Eff.scope update (fun () -> f arg) - -(** NbE helpers *) - -let eval tm = Eval.eval ~env:(Eff.read()).tms tm - -(** Evaluate under the current environment augmented by `arg` *) -(* TODO: this is kind of inelegant, can we do better? *) -let eval_at arg = Eval.eval ~env:((Eff.read()).tms <: arg) - -let quote v = Quote.quote ~size:(Eff.read()).size v - -(** Pretty-printing helpers *) - -let pp () = let names = (Eff.read()).names in fun fmt tm -> - Syntax.Pretty.pp fmt (tm, names) - -(** Main algorithm *) - -let rec check ~(tm : A.expr) ~(tp : D.t) : S.t = - Reporter.tracef ?loc:tm.loc "when checking against the type @[%a@]" (pp()) (quote tp) @@ fun () -> - match tm.value with - | A.Pi ((name, base), fam) -> begin match tp with - | D.Type -> - let base = check ~tm:base ~tp in - let fam = bind ~name:name.value ~tp:(eval base) @@ fun _ -> check ~tm:fam ~tp in - S.Pi (name.value, base, fam) - | _ -> Reporter.fatalf Reporter.Message.IllTyped "expected an element of type @[%a@], but found an element of a universe" (pp()) (quote tp) end - | A.Lam (name, body) -> begin match tp with - | D.Pi (_, base, fam) -> - let body = bind ~name:name.value ~tp:base @@ fun arg -> - let fib = Eval.inst_clo fam arg in - check ~tm:body ~tp:fib in - S.Lam (name.value, body) - | _ -> Reporter.fatalf Reporter.Message.IllTyped "expected an element of type @[%a@], but found an element of a Pi type" (pp()) (quote tp) - end - | A.Sg ((name, base), fam) -> begin match tp with - | D.Type -> - let base = check ~tm:base ~tp in - let fam = bind ~name:name.value ~tp:(eval base) @@ fun _ -> check ~tm:fam ~tp in - S.Sg (name.value, base, fam) - | _ -> Reporter.fatalf Reporter.Message.IllTyped "expected an element of type @[%a@], but found an element of a universe" (pp()) (quote tp) end - | A.Pair (fst, snd) -> begin match tp with - | D.Sg (_, base, fam) -> - let fst = check ~tm:fst ~tp:base in - let fib = Eval.inst_clo fam (eval fst) in - let snd = check ~tm:snd ~tp:fib in - S.Pair (fst, snd) - | _ -> Reporter.fatalf Reporter.Message.IllTyped "expected an element of type @[%a@], but found an element of a Sigma type" (pp()) (quote tp) - end - | A.Type -> begin match tp with (* TODO type-in-type *) - | D.Type -> S.Type - | _ -> Reporter.fatalf Reporter.Message.IllTyped "expected an element of type @[%a@], but found an element of a universe" (pp()) (quote tp) - end - | A.Bool -> begin match tp with - | D.Type -> S.Bool - | _ -> Reporter.fatalf Reporter.Message.IllTyped "expected an element of type @[%a@], but found an element of a universe" (pp()) (quote tp) - end - | A.True -> begin match tp with - | D.Bool -> S.True - | _ -> Reporter.fatalf Reporter.Message.IllTyped "expected an element of type @[%a@], but found an element of type Bool" (pp()) (quote tp) - end - | A.False -> begin match tp with - | D.Bool -> S.False - | _ -> Reporter.fatalf Reporter.Message.IllTyped "expected an element of type @[%a@], but found an element of type Bool" (pp()) (quote tp) - end - | _ -> let (inferred_tp, tm) = infer tm in begin - try Conversion.equate ~size:((Eff.read()).size) inferred_tp tp with - | Conversion.Unequal -> - Reporter.fatalf Reporter.Message.IllTyped "expected an element of type @[%a@], but found an element of type @[%a@]" (pp()) (quote tp) (pp()) (quote inferred_tp) - end; - tm - -and infer (tm : A.expr) : D.t * S.t = - Reporter.tracef ?loc:tm.loc "when inferring the type" @@ fun () -> - match tm.value with - | A.Var name -> lookup name - | A.Check (tm, tp) -> - let tp = eval @@ check ~tp:D.Type ~tm:tp in - let tm = check ~tp ~tm in - (tp, tm) - | A.App (fn, arg) -> begin match infer fn with - | (D.Pi (_, base, fam), fn) -> - let arg = check ~tm:arg ~tp:base in - let tp = Eval.inst_clo fam (eval arg) in - let tm = S.App (fn, arg) in - (tp, tm) - | _ -> Reporter.fatalf Reporter.Message.IllTyped "cannot apply this term because it is not a function" - end - | A.Fst p -> begin match infer p with - | (D.Sg (_, base, _), p) -> (base, S.Fst p) - | _ -> Reporter.fatalf Reporter.Message.IllTyped "cannot apply first projection to this term because it is not of sigma type" - end - | A.Snd p -> begin match infer p with - | (D.Sg (_, _, fam), p) -> - let tp = Eval.inst_clo fam (eval (S.Fst p)) in - let tm = S.Snd p in - (tp, tm) - | _ -> Reporter.fatalf Reporter.Message.IllTyped "cannot apply second projection to this term because it is of sigma type" - end - | A.BoolElim { motive_var; motive_body; true_case; false_case; scrut } -> - let scrut = check ~tm:scrut ~tp:D.Bool in - let motive = bind ~name:motive_var.value ~tp:D.Bool @@ fun _ -> - check ~tm:motive_body ~tp:D.Type in - let motive_true = eval_at D.True motive in - let motive_false = eval_at D.False motive in - let motive_scrut = eval_at (eval scrut) motive in - let true_case = check ~tm:true_case ~tp:motive_true in - let false_case = check ~tm:false_case ~tp:motive_false in - let tm = S.BoolElim { motive_var = motive_var.value; motive; true_case; false_case; scrut } in - (motive_scrut, tm) - | _ -> Reporter.fatalf Reporter.Message.CannotInferType "cannot infer type" - -let empty_env : env = { - tps = Emp; - tms = Emp; - names = Emp; - size = 0; -} - -let infer_toplevel (tm : A.expr) = Eff.run ~env:empty_env @@ fun () -> infer tm
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