add bs.return nullable support, no nested parens

Author: bobzhang

jscomp/bin/bsdep.ml

@@ -30910,6 +30910,7 @@ let process_external_attributes
                 begin match txt with 
                   | "undefined_to_opt" -> Return_undefined_to_opt
                   | "null_to_opt" -> Return_null_to_opt
+                  | "nullable"
                   | "null_undefined_to_opt" -> Return_null_undefined_to_opt
                   | "identity" -> Return_identity 
                   | _ ->

jscomp/bin/bsppx.ml

@@ -12921,6 +12921,7 @@ let process_external_attributes
                 begin match txt with 
                   | "undefined_to_opt" -> Return_undefined_to_opt
                   | "null_to_opt" -> Return_null_to_opt
+                  | "nullable"
                   | "null_undefined_to_opt" -> Return_null_undefined_to_opt
                   | "identity" -> Return_identity 
                   | _ ->

jscomp/bin/whole_compiler.ml

@@ -86373,13 +86373,16 @@ and
     then P.paren_group f 1 action 
     else action ()
   | Is_null_undefined_to_boolean e ->
-    P.paren_group f 1 (fun _ -> 
+    let action = (fun _ -> 
         let cxt = expression 1 cxt f e in 
         P.space f ;
         P.string f "==";
         P.space f ;
         P.string f L.null;
-        cxt) 
+        cxt)  in 
+    if l > 0 then      
+      P.paren_group f 1 action
+    else action ()  
 
   | Caml_not e ->
     expression_desc cxt l f (Bin (Minus, E.one_int_literal, e))
@@ -104068,6 +104071,7 @@ let process_external_attributes
                 begin match txt with 
                   | "undefined_to_opt" -> Return_undefined_to_opt
                   | "null_to_opt" -> Return_null_to_opt
+                  | "nullable"
                   | "null_undefined_to_opt" -> Return_null_undefined_to_opt
                   | "identity" -> Return_identity 
                   | _ ->

jscomp/core/js_dump.ml

@@ -837,13 +837,16 @@ and
     then P.paren_group f 1 action 
     else action ()
   | Is_null_undefined_to_boolean e ->
-    P.paren_group f 1 (fun _ -> 
+    let action = (fun _ -> 
         let cxt = expression 1 cxt f e in 
         P.space f ;
         P.string f "==";
         P.space f ;
         P.string f L.null;
-        cxt) 
+        cxt)  in 
+    if l > 0 then      
+      P.paren_group f 1 action
+    else action ()  
 
   | Caml_not e ->
     expression_desc cxt l f (Bin (Minus, E.one_int_literal, e))

jscomp/syntax/ast_external_attributes.ml

@@ -350,6 +350,7 @@ let process_external_attributes
                 begin match txt with 
                   | "undefined_to_opt" -> Return_undefined_to_opt
                   | "null_to_opt" -> Return_null_to_opt
+                  | "nullable"
                   | "null_undefined_to_opt" -> Return_null_undefined_to_opt
                   | "identity" -> Return_identity 
                   | _ ->

jscomp/test/bs_splice_partial.js

@@ -12,6 +12,15 @@ function test_hi(x) {
   }
 }
 
+function test_hi__2(x) {
+  var match = x.hi__2();
+  if (match == null) {
+    return 1;
+  } else {
+    return 2;
+  }
+}
+
 function test_cb(x) {
   Curry._1(x.cb("hI", 1, 2, 3), 3);
   Curry._1(x.cb("hI", 1, 2, 3), 3);
@@ -23,7 +32,8 @@ function f(x) {
   return /* () */0;
 }
 
-exports.test_hi = test_hi;
-exports.test_cb = test_cb;
-exports.f       = f;
+exports.test_hi    = test_hi;
+exports.test_hi__2 = test_hi__2;
+exports.test_cb    = test_cb;
+exports.f          = f;
 /* No side effect */

jscomp/test/bs_splice_partial.ml

@@ -35,6 +35,15 @@ let test_hi x =
     | Some y -> Js.log y ; 2
 
 
+external hi__2 : int array -> int option = ""
+    [@@bs.splice] [@@bs.return nullable ]
+    [@@bs.send.pipe:int]
+
+let test_hi__2 x = 
+    match x |> hi__2 [||]with 
+    | None -> 1    
+    | Some _ -> 2 
+
 type id = int -> int 
 
 external cb : string -> int array -> id = ""    

jscomp/test/return_check.js

@@ -73,7 +73,7 @@ function f_null(xs, i) {
 
 function f_null_undefined(xs, i) {
   var match = xs[i];
-  if ((match == null)) {
+  if (match == null) {
     throw [
           Caml_builtin_exceptions.assert_failure,
           [

jscomp/test/test_zero_nullable.js

@@ -196,15 +196,15 @@ var Test_def = /* module */[
 ];
 
 function f1$2(x) {
-  if ((x == null)) {
+  if (x == null) {
     return 3;
   } else {
     return x + 1 | 0;
   }
 }
 
 function f2$2(x) {
-  if ((x == null)) {
+  if (x == null) {
     return 3;
   } else {
     return x + 1 | 0;
@@ -213,7 +213,7 @@ function f2$2(x) {
 
 function f5$2(h, _) {
   var u = Curry._1(h, 32);
-  if ((u == null)) {
+  if (u == null) {
     return 3;
   } else {
     return u + 1 | 0;
@@ -223,7 +223,7 @@ function f5$2(h, _) {
 function f4$2(h, x) {
   var u = Curry._1(h, 32);
   var v = 32 + x | 0;
-  if ((u == null)) {
+  if (u == null) {
     return 1 + v | 0;
   } else {
     return u + 1 | 0;
@@ -239,9 +239,9 @@ function f7$2(x) {
 }
 
 function f8$2(x) {
-  if ((x == null)) {
+  if (x == null) {
     return 2;
-  } else if ((x == null)) {
+  } else if (x == null) {
     return 1;
   } else {
     return 0;
@@ -251,7 +251,7 @@ function f8$2(x) {
 var u$2 = f8$2(/* None */0);
 
 function f9$2(x) {
-  if ((x == null)) {
+  if (x == null) {
     return /* None */0;
   } else {
     return [x];