-let transProg _ =
- failwith "Not implemented: Tiger_semant.transProg"
+module List = ListLabels
+
+module A = Tiger_absyn
+module Env = Tiger_env
+module E = Tiger_error
+module Translate = Tiger_translate
+module Type = Tiger_env_type
+module Value = Tiger_env_value
+
+(* The only reason for having this seemingly-superfluous inner module is to
+ * have this nice signature as a summary of what each function does. *)
+module Semant : sig
+ type expty =
+ { exp : Translate.exp
+ ; ty : Type.t
+ }
+
+ (* Violating normal naming convention just to make it easier to follow
+ * Appel's
+ *)
+ val transExp : env:Env.t -> A.exp -> expty
+ val transVar : env:Env.t -> A.var -> expty
+ val transDec : env:Env.t -> A.dec -> Env.t
+ val transTy : env:Env.t -> A.ty -> Type.t (* needs only type env *)
+end = struct
+ type expty =
+ { exp : Translate.exp
+ ; ty : Type.t
+ }
+
+ let unimplemented () =
+ failwith "unimplemented"
+
+ let return ty = {exp = (); ty}
+ let return_unit = return Type.Unit
+ let return_nil = return Type.Nil
+ let return_int = return Type.Int
+ let return_string = return Type.String
+
+ let env_get_typ ~sym ~env ~pos : Type.t =
+ match Env.get_typ env sym with
+ | Some ty -> ty
+ | None -> E.raise (E.Unknown_type {ty_id=sym; pos})
+
+ let env_get_val ~sym ~env ~pos : Value.t =
+ match Env.get_val env sym with
+ | Some ty -> ty
+ | None -> E.raise (E.Unknown_id {id=sym; pos})
+
+ let check_same {exp=_; ty=ty_left} {exp=_; ty=ty_right} ~pos : unit =
+ if Type.is_equal ty_left ty_right then
+ ()
+ else
+ E.raise (E.Wrong_type {expected=ty_left; given=ty_right; pos})
+
+ let check_int expty ~pos : unit =
+ check_same {exp=(); ty=Type.Int} expty ~pos
+
+ let rec transExp ~env exp =
+ let rec trexp exp =
+ (match exp with
+ | A.NilExp ->
+ return_nil
+ | A.IntExp _ ->
+ return_int
+ | A.StringExp {string=_; _} ->
+ return_string
+ | A.CallExp {func=_; args=_; pos=_} ->
+ unimplemented ()
+ | A.OpExp {oper; left; right; pos} ->
+ trop oper ~left ~right ~pos
+ | A.RecordExp {fields=_; typ=_; pos=_} ->
+ unimplemented ()
+ | A.SeqExp exps ->
+ (* Ignoring value because we only care if a type-checking exception
+ * is raised in one of trexp calls: *)
+ List.iter exps ~f:(fun (exp, _) -> ignore (trexp exp));
+ return_unit
+ | A.AssignExp {var; exp; pos} ->
+ check_same (trvar var) (trexp exp) ~pos;
+ (* TODO: Add var->exp to val env? *)
+ return_unit
+ | A.IfExp {test; then'; else'; pos} ->
+ (* test : must be int, because we have no bool *)
+ (* then : must equal else *)
+ (* else : must equal then or be None *)
+ check_int (trexp test) ~pos;
+ (match (trexp then', else') with
+ | expty_then, None ->
+ expty_then
+ | expty_then, Some else' ->
+ let expty_else = trexp else' in
+ check_same expty_then expty_else ~pos;
+ expty_then
+ )
+ | A.WhileExp {test; body; pos} ->
+ (* test : must be int, because we have no bool *)
+ check_int (trexp test) ~pos;
+ ignore (trexp body); (* Only care if a type-error is raised *)
+ return_unit
+ | A.ForExp {var; lo; hi; body; pos; escape=_} ->
+ check_int (trexp lo) ~pos;
+ check_int (trexp hi) ~pos;
+ (* Only care if a type-error is raised *)
+ ignore (transExp ~env:(Env.set_typ env var Type.Int) body);
+ return_unit
+ | A.BreakExp _ ->
+ return_unit
+ | A.LetExp {decs=_; body=_; _} ->
+ unimplemented ()
+ | A.ArrayExp {typ=_; size=_; init=_; _} ->
+ unimplemented ()
+ | A.VarExp var ->
+ trvar var
+ )
+ and trvar =
+ (function
+ | A.SimpleVar {symbol=sym; pos} ->
+ (match env_get_val ~sym ~env ~pos with
+ | Value.Fun _ -> E.raise (E.Id_is_a_function {id=sym; pos})
+ | Value.Var {ty} -> return ty
+ )
+ | A.FieldVar {var; symbol; pos} ->
+ let {exp=_; ty} = trvar var in
+ Type.if_record
+ ty
+ ~f:(fun fields ->
+ (match List.assoc_opt symbol fields with
+ | None ->
+ E.raise
+ (E.No_such_field_in_record {field=symbol; record=ty; pos})
+ | Some ty ->
+ return ty
+ )
+ )
+ ~otherwise:(fun () -> E.raise (E.Exp_not_a_record {ty; pos}))
+ | A.SubscriptVar {var=_; exp=_; pos=_} ->
+ unimplemented ()
+ )
+ and trop oper ~left ~right ~pos =
+ let expty_left = trexp left in
+ let expty_right = trexp right in
+ check_same expty_left expty_right ~pos;
+ let {exp=_; ty} = expty_left in
+ let module T = Type in
+ (match oper with
+ (* Arithmetic: int *)
+ | A.PlusOp
+ | A.MinusOp
+ | A.TimesOp
+ | A.DivideOp ->
+ check_int expty_left ~pos;
+ return_int
+ (* Equality: int, string, array, record *)
+ | A.EqOp
+ | A.NeqOp ->
+ if (T.is_int ty)
+ || (T.is_string ty)
+ || (T.is_array ty)
+ || (T.is_record ty)
+ then
+ return ty
+ else
+ E.raise (E.Invalid_operand_type
+ { oper
+ ; valid = ["int"; "string"; "array"; "record"]
+ ; given = ty
+ ; pos
+ })
+ (* Order: int, string *)
+ | A.LtOp
+ | A.LeOp
+ | A.GtOp
+ | A.GeOp ->
+ if (T.is_int ty)
+ || (T.is_string ty)
+ then
+ return ty
+ else
+ E.raise (E.Invalid_operand_type
+ { oper
+ ; valid = ["int"; "string"]
+ ; given = ty
+ ; pos
+ })
+ )
+ in
+ trexp exp
+
+ let transVar ~env:_ var =
+ (match var with
+ | A.SimpleVar {symbol=_; _} ->
+ unimplemented ()
+ | A.FieldVar {var=_; symbol=_; _} ->
+ unimplemented ()
+ | A.SubscriptVar {var=_; exp=_; _} ->
+ unimplemented ()
+ )
+
+ let transDec ~env:_ dec =
+ (match dec with
+ | A.VarDec {name=_; typ=_; init=_; pos=_; escape=_} ->
+ unimplemented ()
+ | A.TypeDecs _ ->
+ unimplemented ()
+ | A.FunDecs _ ->
+ unimplemented ()
+ )
+
+ let transTy ~env:_ typ =
+ (match typ with
+ | A.NameTy {symbol = _; pos = _} ->
+ unimplemented ()
+ | A.RecordTy _ ->
+ unimplemented ()
+ | A.ArrayTy {symbol = _; pos = _} ->
+ unimplemented ()
+ )
+end
+
+let transProg absyn =
+ let open Semant in
+ let {exp = _; ty = _} = transExp absyn ~env:Env.base in
+ ()
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