Implement for..of loops for arrays

Author: cknitt

analysis/reanalyze/src/Arnold.ml

@@ -979,6 +979,9 @@ module Compile = struct
     | Texp_for _ ->
       notImplemented "Texp_for";
       assert false
+    | Texp_for_of _ ->
+      notImplemented "Texp_for_of";
+      assert false
     | Texp_send _ ->
       notImplemented "Texp_send";
       assert false

analysis/reanalyze/src/SideEffects.ml

@@ -59,6 +59,8 @@ let rec exprNoSideEffects (expr : Typedtree.expression) =
   | Texp_for (_id, _pat, e1, e2, _dir, e3) ->
     e1 |> exprNoSideEffects && e2 |> exprNoSideEffects
     && e3 |> exprNoSideEffects
+  | Texp_for_of (_id, _pat, e1, e2) ->
+    e1 |> exprNoSideEffects && e2 |> exprNoSideEffects
   | Texp_send _ -> false
   | Texp_letexception (_ec, e) -> e |> exprNoSideEffects
   | Texp_pack _ -> false

analysis/src/Utils.ml

@@ -100,6 +100,7 @@ let identifyPexp pexp =
   | Pexp_sequence _ -> "Pexp_sequence"
   | Pexp_while _ -> "Pexp_while"
   | Pexp_for _ -> "Pexp_for"
+  | Pexp_for_of _ -> "Pexp_for_of"
   | Pexp_constraint _ -> "Pexp_constraint"
   | Pexp_coerce _ -> "Pexp_coerce"
   | Pexp_send _ -> "Pexp_send"

compiler/core/j.ml

@@ -264,6 +264,7 @@ and statement_desc =
       * for_ident
       * for_direction
       * block
+  | ForOf of for_ident * expression * block
   | Continue
   | Break (* only used when inline a fucntion *)
   | Return of expression

compiler/core/js_analyzer.ml

@@ -135,8 +135,8 @@ let no_side_effect_obj =
         | Throw _ | Debugger | Break | Variable _ | Continue ->
           raise_notrace Not_found
         | Exp e -> self.expression self e
-        | Int_switch _ | String_switch _ | ForRange _ | If _ | While _ | Block _
-        | Return _ | Try _ ->
+        | Int_switch _ | String_switch _ | ForRange _ | ForOf _ | If _ | While _
+        | Block _ | Return _ | Try _ ->
           super.statement self s);
     expression =
       (fun _ s ->
@@ -255,7 +255,7 @@ and eq_statement ({statement_desc = x0} : J.statement)
     match y0 with
     | Block ys0 -> eq_block xs0 ys0
     | _ -> false)
-  | Variable _ | If _ | While _ | ForRange _ | Continue | Int_switch _
+  | Variable _ | If _ | While _ | ForRange _ | ForOf _ | Continue | Int_switch _
   | String_switch _ | Throw _ | Try _ ->
     false
 

compiler/core/js_dump.ml

@@ -1478,6 +1478,21 @@ and statement_desc top cxt f (s : J.statement_desc) : cxt =
           brace_block cxt f s)
     in
     action cxt
+  | ForOf (id, iterable, s) ->
+    P.vgroup f 0 (fun _ ->
+        P.group f 0 (fun _ ->
+            P.string f L.for_;
+            P.space f;
+            P.paren_group f 1 (fun _ ->
+                P.string f L.let_;
+                P.space f;
+                ignore (Ext_pp_scope.ident cxt f id);
+                P.space f;
+                P.string f L.of_;
+                P.space f;
+                ignore (expression ~level:0 cxt f iterable)));
+        P.space f;
+        brace_block cxt f s)
   | Continue ->
     continue f;
     cxt

compiler/core/js_dump_lit.ml

@@ -90,6 +90,8 @@ let if_ = "if"
 
 let for_ = "for"
 
+let of_ = "of"
+
 let try_ = "try"
 
 let finally = "finally"

compiler/core/js_fold.ml

@@ -241,6 +241,11 @@ class fold =
         let _self = _self#for_direction _x3 in
         let _self = _self#block _x4 in
         _self
+      | ForOf (_x0, _x1, _x2) ->
+        let _self = _self#for_ident _x0 in
+        let _self = _self#expression _x1 in
+        let _self = _self#block _x2 in
+        _self
       | Continue -> _self
       | Break -> _self
       | Return _x0 ->

compiler/core/js_pass_scope.ml

@@ -238,7 +238,7 @@ let record_scope_pass =
     statement =
       (fun self state x ->
         match x.statement_desc with
-        | ForRange (_, _, loop_id, _, _) ->
+        | ForRange (_, _, loop_id, _, _) | ForOf (loop_id, _, _) ->
           (* TODO: simplify definition of For *)
           let {
             defined_idents = defined_idents';

compiler/core/js_record_fold.ml

@@ -245,6 +245,11 @@ let statement_desc : 'a. ('a, statement_desc) fn =
     let st = for_direction _self st _x3 in
     let st = _self.block _self st _x4 in
     st
+  | ForOf (_x0, _x1, _x2) ->
+    let st = _self.for_ident _self st _x0 in
+    let st = _self.expression _self st _x1 in
+    let st = _self.block _self st _x2 in
+    st
   | Continue -> st
   | Break -> st
   | Return _x0 ->