add bitxor (^) unified operator (#7216)

MiryangJung · cometkim · cknitt · web-flow · commit a7d34c733c45 · 2025-03-25T14:46:35.000+01:00
* add add lxor (^) unified operator

* add bitxor

Co-authored-by: Hyeseong Kim &lt;hey@hyeseong.kim&gt;

* Update compiler/syntax/src/res_diagnostics.ml

Co-authored-by: Christoph Knittel &lt;christoph@knittel.cc&gt;

* update the test output

* CHANGELOG: Add unified bitwise (`^`) operator to the list of changes

* Update CHANGELOG.md

---------

Co-authored-by: Hyeseong Kim &lt;hey@hyeseong.kim&gt;
Co-authored-by: Christoph Knittel &lt;christoph@knittel.cc&gt;
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -23,6 +23,7 @@
 - Experimental: Support nested/inline record types - records defined inside of other records, without needing explicit separate type definitions. https://github.com/rescript-lang/rescript/pull/7241
 - Add unified exponentiation (`**`) operator for numeric types using ES7 `**`. https://github.com/rescript-lang/rescript-compiler/pull/7153
 - Rename `raise` to `throw` to align with JavaScript vocabulary. `raise` has been deprecated. https://github.com/rescript-lang/rescript/pull/7346
+- Add unified bitwise (`^`) operator. https://github.com/rescript-lang/rescript/pull/7216
 
 #### :boom: Breaking Change
 
diff --git a/compiler/ml/unified_ops.ml b/compiler/ml/unified_ops.ml
@@ -174,6 +174,19 @@ let entries =
           string = None;
         };
     };
+    {
+      path = builtin "^";
+      name = "%bitxor";
+      form = Binary;
+      specialization =
+        {
+          int = Pxorint;
+          bool = None;
+          float = None;
+          bigint = Some Pxorbigint;
+          string = None;
+        };
+    };
   |]
 
 let index_by_path =
diff --git a/compiler/syntax/src/res_diagnostics.ml b/compiler/syntax/src/res_diagnostics.ml
@@ -65,14 +65,8 @@ let explain t =
   | UnclosedTemplate ->
     "Did you forget to close this template expression with a backtick?"
   | UnclosedComment -> "This comment seems to be missing a closing `*/`"
-  | UnknownUchar uchar -> (
-    match uchar with
-    | '^' ->
-      "Not sure what to do with this character.\n"
-      ^ "  If you're trying to dereference a mutable value, use \
-         `myValue.contents` instead.\n"
-      ^ "  To concatenate strings, use `\"a\" ++ \"b\"` instead."
-    | _ -> "Not sure what to do with this character.")
+  | UnknownUchar uchar ->
+    "Not sure what to do with this character: \"" ^ Char.escaped uchar ^ "\"."
   | Expected {context; token = t} ->
     let hint =
       match context with
diff --git a/compiler/syntax/src/res_parens.ml b/compiler/syntax/src/res_parens.ml
@@ -162,8 +162,7 @@ let rhs_binary_expr_operand parent_operator rhs =
           };
         args = [(_, _left); (_, _right)];
       }
-    when ParsetreeViewer.is_binary_operator operator
-         && not (operator_loc.loc_ghost && operator = "++") ->
+    when ParsetreeViewer.not_ghost_operator operator operator_loc ->
     let prec_parent = ParsetreeViewer.operator_precedence parent_operator in
     let prec_child = ParsetreeViewer.operator_precedence operator in
     prec_parent == prec_child
@@ -180,8 +179,7 @@ let flatten_operand_rhs parent_operator rhs =
           };
         args = [(_, _left); (_, _right)];
       }
-    when ParsetreeViewer.is_binary_operator operator
-         && not (operator_loc.loc_ghost && operator = "++") ->
+    when ParsetreeViewer.not_ghost_operator operator operator_loc ->
     let prec_parent = ParsetreeViewer.operator_precedence parent_operator in
     let prec_child = ParsetreeViewer.operator_precedence operator in
     prec_parent >= prec_child || rhs.pexp_attributes <> []
diff --git a/compiler/syntax/src/res_parsetree_viewer.ml b/compiler/syntax/src/res_parsetree_viewer.ml
@@ -272,11 +272,12 @@ let operator_precedence operator =
   | ":=" -> 1
   | "||" -> 2
   | "&&" -> 3
-  | "==" | "===" | "<" | ">" | "!=" | "<>" | "!==" | "<=" | ">=" | "|>" -> 4
-  | "+" | "+." | "-" | "-." | "++" -> 5
-  | "*" | "*." | "/" | "/." | "%" -> 6
-  | "**" -> 7
-  | "#" | "##" | "->" -> 8
+  | "^" -> 4
+  | "==" | "===" | "<" | ">" | "!=" | "<>" | "!==" | "<=" | ">=" | "|>" -> 5
+  | "+" | "+." | "-" | "-." | "++" -> 6
+  | "*" | "*." | "/" | "/." | "%" -> 7
+  | "**" -> 8
+  | "#" | "##" | "->" -> 9
   | _ -> 0
 
 let is_unary_operator operator =
@@ -295,15 +296,17 @@ let is_unary_expression expr =
     true
   | _ -> false
 
-(* TODO: tweak this to check for ghost ^ as template literal *)
 let is_binary_operator operator =
   match operator with
   | ":=" | "||" | "&&" | "==" | "===" | "<" | ">" | "!=" | "!==" | "<=" | ">="
   | "|>" | "+" | "+." | "-" | "-." | "++" | "*" | "*." | "/" | "/." | "**"
-  | "->" | "<>" | "%" ->
+  | "->" | "<>" | "%" | "^" ->
     true
   | _ -> false
 
+let not_ghost_operator operator (loc : Location.t) =
+  is_binary_operator operator && not (loc.loc_ghost && operator = "++")
+
 let is_binary_expression expr =
   match expr.pexp_desc with
   | Pexp_apply
@@ -315,9 +318,7 @@ let is_binary_expression expr =
           };
         args = [(Nolabel, _operand1); (Nolabel, _operand2)];
       }
-    when is_binary_operator operator
-         && not (operator_loc.loc_ghost && operator = "++")
-         (* template literal *) ->
+    when not_ghost_operator operator operator_loc ->
     true
   | _ -> false
 
diff --git a/compiler/syntax/src/res_parsetree_viewer.mli b/compiler/syntax/src/res_parsetree_viewer.mli
@@ -65,6 +65,7 @@ val is_huggable_rhs : Parsetree.expression -> bool
 
 val operator_precedence : string -> int
 
+val not_ghost_operator : string -> Location.t -> bool
 val is_unary_expression : Parsetree.expression -> bool
 val is_binary_operator : string -> bool
 val is_binary_expression : Parsetree.expression -> bool
diff --git a/compiler/syntax/src/res_scanner.ml b/compiler/syntax/src/res_scanner.ml
@@ -834,6 +834,9 @@ let rec scan scanner =
       | _ ->
         next scanner;
         Token.Band)
+    | '^' ->
+      next scanner;
+      Token.Caret
     | ':' -> (
       match peek scanner with
       | '=' ->
diff --git a/compiler/syntax/src/res_token.ml b/compiler/syntax/src/res_token.ml
@@ -78,6 +78,7 @@ type t =
   | Land
   | Lor
   | Band (* Bitwise and: & *)
+  | Caret
   | BangEqual
   | BangEqualEqual
   | LessEqual
@@ -102,14 +103,15 @@ let precedence = function
   | HashEqual | ColonEqual -> 1
   | Lor -> 2
   | Land -> 3
+  | Caret -> 4
   | Equal | EqualEqual | EqualEqualEqual | LessThan | GreaterThan | BangEqual
   | BangEqualEqual | LessEqual | GreaterEqual | BarGreater ->
-    4
-  | Plus | PlusDot | Minus | MinusDot | PlusPlus -> 5
-  | Asterisk | AsteriskDot | Forwardslash | ForwardslashDot | Percent -> 6
-  | Exponentiation -> 7
-  | MinusGreater -> 8
-  | Dot -> 9
+    5
+  | Plus | PlusDot | Minus | MinusDot | PlusPlus -> 6
+  | Asterisk | AsteriskDot | Forwardslash | ForwardslashDot | Percent -> 7
+  | Exponentiation -> 8
+  | MinusGreater -> 9
+  | Dot -> 10
   | _ -> 0
 
 let to_string = function
@@ -189,6 +191,7 @@ let to_string = function
   | Of -> "of"
   | Lor -> "||"
   | Band -> "&"
+  | Caret -> "^"
   | Land -> "&&"
   | BangEqual -> "!="
   | BangEqualEqual -> "!=="
diff --git a/runtime/Pervasives.res b/runtime/Pervasives.res
@@ -63,6 +63,7 @@ external \"/": ('a, 'a) => 'a = "%div"
 external \"%": ('a, 'a) => 'a = "%mod"
 external mod: ('a, 'a) => 'a = "%mod"
 external \"**": ('a, 'a) => 'a = "%pow"
+external \"^": ('a, 'a) => 'a = "%bitxor"
 
 /* Comparisons */
 /* Note: Later comparisons will be converted to unified operations too */
diff --git a/runtime/Pervasives_mini.res b/runtime/Pervasives_mini.res
@@ -31,6 +31,7 @@ external \"/": (int, int) => int = "%divint"
 external \"%": (int, int) => int = "%modint"
 external mod: (int, int) => int = "%modint"
 external \"**": (int, int) => int = "%powint"
+external \"^": (int, int) => int = "%bitxorint"
 
 /* Comparisons */
 /* Note: Later comparisons will be converted to unified operations too */
diff --git a/tests/syntax_tests/data/parsing/errors/pattern/expected/templateLiteral.res.txt b/tests/syntax_tests/data/parsing/errors/pattern/expected/templateLiteral.res.txt
@@ -20,7 +20,7 @@
   6 │ | _ => ()
   7 │ }
 
-  Not sure what to do with this character.
+  Not sure what to do with this character: "$".
 
 
   Syntax error!
diff --git a/tests/syntax_tests/data/parsing/errors/scanner/expected/badCharacter.res.txt b/tests/syntax_tests/data/parsing/errors/scanner/expected/badCharacter.res.txt
@@ -4,7 +4,7 @@
 
   1 │ let $ = 1
 
-  Not sure what to do with this character.
+  Not sure what to do with this character: "$".
 
 
   Syntax error!
diff --git a/tests/syntax_tests/data/parsing/errors/scanner/expected/oldDerefOp.res.txt b/tests/syntax_tests/data/parsing/errors/scanner/expected/oldDerefOp.res.txt
@@ -1,26 +1,23 @@
 
   Syntax error!
-  syntax_tests/data/parsing/errors/scanner/oldDerefOp.res:1:50
+  syntax_tests/data/parsing/errors/scanner/oldDerefOp.res:1:51
 
   1 │ let newVelocity = velocity +. a *. secondPerFrame^;
   2 │ let newX = x +. newVelocity *. secondPerFrame^;
   3 │ 
 
-  Not sure what to do with this character.
-  If you're trying to dereference a mutable value, use `myValue.contents` instead.
-  To concatenate strings, use `"a" ++ "b"` instead.
+  Did you forget to write an expression here?
 
 
   Syntax error!
-  syntax_tests/data/parsing/errors/scanner/oldDerefOp.res:2:46
+  syntax_tests/data/parsing/errors/scanner/oldDerefOp.res:2:47
 
   1 │ let newVelocity = velocity +. a *. secondPerFrame^;
   2 │ let newX = x +. newVelocity *. secondPerFrame^;
   3 │ 
 
-  Not sure what to do with this character.
-  If you're trying to dereference a mutable value, use `myValue.contents` instead.
-  To concatenate strings, use `"a" ++ "b"` instead.
+  Did you forget to write an expression here?
 
-let newVelocity = velocity +. (a *. secondPerFrame)
-let newX = x +. (newVelocity *. secondPerFrame)
+let newVelocity =
+  (velocity +. (a *. secondPerFrame)) ^ ([%rescript.exprhole ])
+let newX = (x +. (newVelocity *. secondPerFrame)) ^ ([%rescript.exprhole ])
diff --git a/tests/syntax_tests/data/parsing/grammar/expressions/binary.res b/tests/syntax_tests/data/parsing/grammar/expressions/binary.res
@@ -28,6 +28,7 @@ let x = z |> @attr while condition { () }
 let x = a + -1 + -2
 let x = a + @attr -1 + @attr -2
 let x = a % a == 0
+let x = a ^ a == 0
 
 // should be interpreted as binary expression not prefix op
 let x = a -b
diff --git a/tests/syntax_tests/data/parsing/grammar/expressions/expected/binary.res.txt b/tests/syntax_tests/data/parsing/grammar/expressions/expected/binary.res.txt
@@ -14,6 +14,7 @@ let x = ((while condition do () done)[@attr ]) z
 let x = (a + (-1)) + (-2)
 let x = (a + (((-1))[@attr ])) + (((-2))[@attr ])
 let x = (a % a) == 0
+let x = a ^ (a == 0)
 let x = a - b
 let x = a -. b
 ;;Constructor (a, b)
diff --git a/tests/syntax_tests/data/printer/expr/binary.res b/tests/syntax_tests/data/printer/expr/binary.res
@@ -54,6 +54,7 @@ let () = (x: int) |> (print_int: int => unit)
 x + y / z
 x / y + z
 x % y * z
+x ^ y + z
 100 * x / total
 2 / 3 * 10 / 2 + 2
 let rotateX = ((range / rect.height) * refY - range / 2) * getXMultiplication(rect.width)
diff --git a/tests/syntax_tests/data/printer/expr/expected/binary.res.txt b/tests/syntax_tests/data/printer/expr/expected/binary.res.txt
@@ -85,6 +85,7 @@ let () = (print_int: int => unit)((x: int))
 x + y / z
 x / y + z
 x % y * z
+x ^ y + z
 100 * x / total
 2 / 3 * 10 / 2 + 2
 let rotateX = (range / rect.height * refY - range / 2) * getXMultiplication(rect.width)
diff --git a/tests/tests/src/belt_int_test.mjs b/tests/tests/src/belt_int_test.mjs
@@ -36,6 +36,7 @@ Mocha.describe("Belt_int_test", () => {
     Test_utils.eq("File \"belt_int_test.res\", line 41, characters 7-14", 6, 6);
     Test_utils.eq("File \"belt_int_test.res\", line 42, characters 7-14", 0, 0);
     Test_utils.eq("File \"belt_int_test.res\", line 43, characters 7-14", 0, 0);
+    Test_utils.eq("File \"belt_int_test.res\", line 44, characters 7-14", 1, 1);
   });
 });
 
diff --git a/tests/tests/src/belt_int_test.res b/tests/tests/src/belt_int_test.res
@@ -41,5 +41,6 @@ describe(__MODULE__, () => {
     eq(__LOC__, 2 * 3, 6)
     eq(__LOC__, 2 / 3, 0)
     eq(__LOC__, 2 % 2, 0)
+    eq(__LOC__, 2 ^ 3, 1)
   })
 })
diff --git a/tests/tests/src/unified_ops_test.mjs b/tests/tests/src/unified_ops_test.mjs
@@ -67,6 +67,14 @@ let pow3 = 2n ** 2n;
 
 let pow_overflow = 0;
 
+function bxor_int(a, b) {
+  return a ^ b;
+}
+
+function bxor_bigint(a, b) {
+  return a ^ b;
+}
+
 let int = 3;
 
 export {
@@ -91,5 +99,7 @@ export {
   pow2,
   pow3,
   pow_overflow,
+  bxor_int,
+  bxor_bigint,
 }
 /* No side effect */
diff --git a/tests/tests/src/unified_ops_test.res b/tests/tests/src/unified_ops_test.res
@@ -26,3 +26,6 @@ let pow2 = 2. ** 2.
 let pow3 = 2n ** 2n
 
 let pow_overflow = 2147483647 ** 2
+
+let bxor_int = (a, b) => a ^ b
+let bxor_bigint = (a: bigint, b) => a ^ b
