Remove unused code

[tiger.ml.git] / compiler / src / lib / tiger / tiger_semant.ml

diff --git a/compiler/src/lib/tiger/tiger_semant.ml b/compiler/src/lib/tiger/tiger_semant.ml
index 5d5d71b..f653e16 100644 (file)
--- a/compiler/src/lib/tiger/tiger_semant.ml
+++ b/compiler/src/lib/tiger/tiger_semant.ml
@@ -19,18 +19,19 @@ module Semant : sig
    * 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 *)
+
+  (* transVar does not seem to be needed, as trvar handles all our cases.
+   * Am I wrong?
+   *
+   * val transVar : env:Env.t -> A.var -> expty
+   *
+   *)
 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
@@ -57,6 +58,7 @@ end = struct
     check_same {exp=(); ty=Type.Int} expty ~pos
 
   (* TODO: actual_ty *)
+  (* TODO: mutual recursion *)
 
   let rec transExp ~env exp =
     let rec trexp exp =
@@ -102,6 +104,7 @@ end = struct
           (* 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));
+          (* FIXME: Return type of last expression, not unit. *)
           return_unit
       | A.AssignExp {var; exp; pos} ->
           check_same (trvar var) (trexp exp) ~pos;
@@ -133,8 +136,13 @@ end = struct
           return_unit
       | A.BreakExp _ ->
           return_unit
-      | A.LetExp {decs=_; body=_; _} ->
-          unimplemented ()
+      | A.LetExp {decs; body; pos=_} ->
+          (* (1) decs augment env *)
+          (* (2) body checked against the new env *)
+          let env =
+            List.fold_left decs ~init:env ~f:(fun env dec -> transDec dec ~env)
+          in
+          transExp body ~env
       | A.ArrayExp {typ; size; init; pos} ->
           check_int (trexp size) ~pos;
           let ty = env_get_typ ~sym:typ ~env ~pos in
@@ -228,39 +236,70 @@ end = struct
       )
     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 =
+  and transDec ~(env : Env.t) (dec : A.dec) : Env.t =
     (match dec with
-    | A.VarDec {name=_; typ=_; init=_; pos=_; escape=_} ->
-        unimplemented ()
-    | A.TypeDecs _ ->
-        unimplemented ()
-    | A.FunDecs _ ->
-        unimplemented ()
+    | A.VarDec {name; typ=typ_opt; init; pos=pos_outter; escape=_} ->
+        let ty =
+          (match (typ_opt, transExp ~env init) with
+          | None, {ty; exp=()} ->
+              ty
+          | Some (sym, pos_inner), expty_init ->
+              let ty = env_get_typ ~sym ~env ~pos:pos_inner in
+              check_same {exp=(); ty} expty_init ~pos:pos_outter;
+              ty
+          )
+        in
+        Env.set_val env name (Value.Var {ty})
+    | A.TypeDecs typedecs ->
+        List.fold_left typedecs ~init:env ~f:(
+          fun env (A.TypeDec {name; ty; pos=_}) ->
+            let ty = transTy ~env ty in
+            Env.set_typ env name ty
+        )
+    | A.FunDecs fundecs ->
+        List.fold_left fundecs ~init:env ~f:(
+          fun env (A.FunDec {name; params; result; body; pos=_}) ->
+            let (env_for_body, formals_in_reverse_order) =
+              List.fold_left params ~init:(env, []) ~f:(
+                fun (env, formals) (A.Field {name; escape=_; typ; pos}) ->
+                  let ty = env_get_typ ~env ~sym:typ ~pos in
+                  let env = Env.set_val env name (Value.Var {ty}) in
+                  (env, ty :: formals)
+              )
+            in
+            (* ignore because we only care if an exception is raised *)
+            ignore (transExp ~env:env_for_body body);
+            let formals = List.rev formals_in_reverse_order in
+            let result =
+              match result with
+              | None ->
+                  Type.Unit
+              | Some (sym, pos) ->
+                  env_get_typ ~sym ~env ~pos
+            in
+            Env.set_val env name (Value.Fun {formals; result})
+        )
     )
-
-  let transTy ~env:_ typ =
+  and transTy ~(env : Env.t) (typ : A.ty) : Type.t =
     (match typ with
-    | A.NameTy {symbol = _; pos = _} ->
-        unimplemented ()
-    | A.RecordTy _ ->
-        unimplemented ()
-    | A.ArrayTy {symbol = _; pos = _} ->
-        unimplemented ()
+    | A.NameTy {symbol=sym; pos} ->
+        env_get_typ ~sym ~env ~pos
+    | A.RecordTy fields ->
+        let fields =
+          List.map fields ~f:(fun (A.Field {name; escape=_; typ; pos}) ->
+            let ty = env_get_typ ~sym:typ ~env ~pos in
+            (name, ty)
+          )
+        in
+        Type.new_record fields
+    | A.ArrayTy {symbol=sym; pos} ->
+        let element_ty = env_get_typ ~sym ~env ~pos in
+        Type.new_array element_ty
     )
 end
 
+open Semant
+
 let transProg absyn =
-  let open Semant in
   let {exp = _; ty = _} = transExp absyn ~env:Env.base in
   ()