1 module List = ListLabels
6 module Translate = Tiger_translate
7 module Type = Tiger_env_type
8 module Value = Tiger_env_value
10 (* The only reason for having this seemingly-superfluous inner module is to
11 * have this nice signature as a summary of what each function does. *)
18 (* Violating normal naming convention just to make it easier to follow
21 val transExp : env:Env.t -> A.exp -> expty
22 val transVar : env:Env.t -> A.var -> expty
23 val transDec : env:Env.t -> A.dec -> Env.t
24 val transTy : env:Env.t -> A.ty -> Type.t (* needs only type env *)
31 let unimplemented () =
32 failwith "unimplemented"
34 let return ty = {exp = (); ty}
35 let return_unit = return Type.Unit
36 let return_nil = return Type.Nil
37 let return_int = return Type.Int
38 let return_string = return Type.String
40 let env_get_typ ~sym ~env ~pos : Type.t =
41 match Env.get_typ env sym with
43 | None -> E.raise (E.Unknown_type {ty_id=sym; pos})
45 let env_get_val ~sym ~env ~pos : Value.t =
46 match Env.get_val env sym with
48 | None -> E.raise (E.Unknown_id {id=sym; pos})
50 let check_same {exp=_; ty=ty_left} {exp=_; ty=ty_right} ~pos : unit =
51 if Type.is_equal ty_left ty_right then
54 E.raise (E.Wrong_type {expected=ty_left; given=ty_right; pos})
56 let check_int expty ~pos : unit =
57 check_same {exp=(); ty=Type.Int} expty ~pos
60 (* TODO: mutual recursion *)
62 let rec transExp ~env exp =
69 | A.StringExp {string=_; _} ->
71 | A.CallExp {func; args; pos} ->
72 (match env_get_val ~sym:func ~env ~pos with
73 | Value.Fun {formals; result} ->
74 List.iter2 formals args ~f:(fun ty_expected exp_given ->
75 check_same {exp=(); ty = ty_expected} (trexp exp_given) ~pos;
79 E.raise (E.Id_not_a_function {id=func; pos})
81 | A.OpExp {oper; left; right; pos} ->
82 trop oper ~left ~right ~pos
83 | A.RecordExp {fields=field_exps; typ; pos} ->
84 let ty = env_get_typ ~sym:typ ~env ~pos in
88 List.iter field_exps ~f:(fun (field, exp, pos) ->
89 (match List.assoc_opt field field_tys with
91 check_same {exp=(); ty=field_ty} (trexp exp) ~pos
94 (E.No_such_field_in_record {field; record=ty; pos})
99 E.raise (E.Wrong_type_used_as_record {ty_id=typ; ty; pos})
103 (* Ignoring value because we only care if a type-checking exception
104 * is raised in one of trexp calls: *)
105 List.iter exps ~f:(fun (exp, _) -> ignore (trexp exp));
106 (* FIXME: Return type of last expression, not unit. *)
108 | A.AssignExp {var; exp; pos} ->
109 check_same (trvar var) (trexp exp) ~pos;
110 (* TODO: Add var->exp to val env? *)
112 | A.IfExp {test; then'; else'; pos} ->
113 (* test : must be int, because we have no bool *)
114 (* then : must equal else *)
115 (* else : must equal then or be None *)
116 check_int (trexp test) ~pos;
117 (match (trexp then', else') with
118 | expty_then, None ->
120 | expty_then, Some else' ->
121 let expty_else = trexp else' in
122 check_same expty_then expty_else ~pos;
125 | A.WhileExp {test; body; pos} ->
126 (* test : must be int, because we have no bool *)
127 check_int (trexp test) ~pos;
128 ignore (trexp body); (* Only care if a type-error is raised *)
130 | A.ForExp {var; lo; hi; body; pos; escape=_} ->
131 check_int (trexp lo) ~pos;
132 check_int (trexp hi) ~pos;
133 (* Only care if a type-error is raised *)
134 ignore (transExp ~env:(Env.set_typ env var Type.Int) body);
138 | A.LetExp {decs; body; pos=_} ->
139 (* (1) decs augment env *)
140 (* (2) body checked against the new env *)
142 List.fold_left decs ~init:env ~f:(fun env dec -> transDec dec ~env)
145 | A.ArrayExp {typ; size; init; pos} ->
146 check_int (trexp size) ~pos;
147 let ty = env_get_typ ~sym:typ ~env ~pos in
150 ~f:(fun ty_elements ->
151 check_same {exp=(); ty=ty_elements} (trexp init) ~pos
153 ~otherwise:(fun () ->
154 E.raise (E.Wrong_type_used_as_array {ty_id=typ; ty; pos})
162 | A.SimpleVar {symbol=sym; pos} ->
163 (match env_get_val ~sym ~env ~pos with
164 | Value.Fun _ -> E.raise (E.Id_is_a_function {id=sym; pos})
165 | Value.Var {ty} -> return ty
167 | A.FieldVar {var; symbol; pos} ->
168 let {exp=_; ty} = trvar var in
172 (match List.assoc_opt symbol fields with
175 (E.No_such_field_in_record {field=symbol; record=ty; pos})
180 ~otherwise:(fun () -> E.raise (E.Exp_not_a_record {ty; pos}))
181 | A.SubscriptVar {var; exp; pos} ->
182 let {exp=_; ty} = trvar var in
183 check_int (trexp exp) ~pos;
186 ~f:(fun ty_elements -> return ty_elements)
187 ~otherwise:(fun () -> E.raise (E.Exp_not_an_array {ty; pos}))
189 and trop oper ~left ~right ~pos =
190 let expty_left = trexp left in
191 let expty_right = trexp right in
192 check_same expty_left expty_right ~pos;
193 let {exp=_; ty} = expty_left in
194 let module T = Type in
196 (* Arithmetic: int *)
201 check_int expty_left ~pos;
203 (* Equality: int, string, array, record *)
213 E.raise (E.Invalid_operand_type
215 ; valid = ["int"; "string"; "array"; "record"]
219 (* Order: int, string *)
229 E.raise (E.Invalid_operand_type
231 ; valid = ["int"; "string"]
238 and transDec ~env dec =
240 | A.VarDec {name; typ=typ_opt; init; pos=pos_outter; escape=_} ->
242 (match (typ_opt, transExp ~env init) with
243 | None, {ty; exp=()} ->
245 | Some (sym, pos_inner), expty_init ->
246 let ty = env_get_typ ~sym ~env ~pos:pos_inner in
247 check_same {exp=(); ty} expty_init ~pos:pos_outter;
251 Env.set_val env name (Value.Var {ty})
252 | A.TypeDecs typedecs ->
253 List.fold_left typedecs ~init:env ~f:(
254 fun env (A.TypeDec {name; ty; pos=_}) ->
255 let ty = transTy ~env ty in
256 Env.set_typ env name ty
258 | A.FunDecs fundecs ->
259 List.fold_left fundecs ~init:env ~f:(
260 fun env (A.FunDec {name; params; result; body; pos=_}) ->
261 let (env_for_body, formals_in_reverse_order) =
262 List.fold_left params ~init:(env, []) ~f:(
263 fun (env, formals) (A.Field {name; escape=_; typ; pos}) ->
264 let ty = env_get_typ ~env ~sym:typ ~pos in
265 let env = Env.set_val env name (Value.Var {ty}) in
269 (* ignore because we only care if an exception is raised *)
270 ignore (transExp ~env:env_for_body body);
271 let formals = List.rev formals_in_reverse_order in
277 env_get_typ ~sym ~env ~pos
279 Env.set_val env name (Value.Fun {formals; result})
282 and transTy ~env typ =
284 | A.NameTy {symbol=sym; pos} ->
285 env_get_typ ~sym ~env ~pos
286 | A.RecordTy fields ->
288 List.map fields ~f:(fun (A.Field {name; escape=_; typ; pos}) ->
289 let ty = env_get_typ ~sym:typ ~env ~pos in
293 Type.new_record fields
294 | A.ArrayTy {symbol=sym; pos} ->
295 let element_ty = env_get_typ ~sym ~env ~pos in
296 Type.new_array element_ty
299 let transVar ~env:_ var =
301 | A.SimpleVar {symbol=_; _} ->
303 | A.FieldVar {var=_; symbol=_; _} ->
305 | A.SubscriptVar {var=_; exp=_; _} ->
312 let transProg absyn =
313 let {exp = _; ty = _} = transExp absyn ~env:Env.base in