Add remainder (% aka modulus) operator (#7152)

Resolved #6455

Author: cometkim

CHANGELOG.md

@@ -14,7 +14,8 @@
 
 #### :rocket: New Feature
 
-- Introduce "Unified operators" for arithmetic operators (`+`, `-`, `*`, `/`, `mod`). See https://github.com/rescript-lang/rescript-compiler/pull/7057
+- Introduce "Unified operators" for arithmetic operators (`+`, `-`, `*`, `/`, `mod`). https://github.com/rescript-lang/rescript-compiler/pull/7057
+- Add remainder (`%`, aka modulus) operator. https://github.com/rescript-lang/rescript-compiler/pull/7152
 
 # 12.0.0-alpha.4
 

compiler/ml/unified_ops.ml

@@ -135,6 +135,19 @@ let entries =
           string = None;
         };
     };
+    {
+      path = builtin "%";
+      name = "%mod";
+      form = Binary;
+      specialization =
+        {
+          int = Pmodint Safe;
+          bool = None;
+          float = Some Pmodfloat;
+          bigint = Some Pmodbigint;
+          string = None;
+        };
+    };
     {
       path = builtin "mod";
       name = "%mod";

compiler/syntax/src/res_core.ml

@@ -2221,7 +2221,7 @@ and parse_binary_expr ?(context = OrdinaryExpr) ?a p prec =
        *
        * First case is unary, second is a binary operator.
        * See Scanner.isBinaryOp *)
-      | (Minus | MinusDot | LessThan)
+      | (Minus | MinusDot | LessThan | Percent)
         when (not
                 (Scanner.is_binary_op p.scanner.src p.start_pos.pos_cnum
                    p.end_pos.pos_cnum))

compiler/syntax/src/res_parsetree_viewer.ml

@@ -302,7 +302,7 @@ let operator_precedence operator =
   | "&&" -> 3
   | "=" | "==" | "<" | ">" | "!=" | "<>" | "!==" | "<=" | ">=" | "|>" -> 4
   | "+" | "+." | "-" | "-." | "^" -> 5
-  | "*" | "*." | "/" | "/." -> 6
+  | "*" | "*." | "/" | "/." | "%" -> 6
   | "**" -> 7
   | "#" | "##" | "|." | "|.u" -> 8
   | _ -> 0
@@ -326,7 +326,7 @@ let is_binary_operator operator =
   match operator with
   | ":=" | "||" | "&&" | "=" | "==" | "<" | ">" | "!=" | "!==" | "<=" | ">="
   | "|>" | "+" | "+." | "-" | "-." | "^" | "*" | "*." | "/" | "/." | "**" | "|."
-  | "|.u" | "<>" ->
+  | "|.u" | "<>" | "%" ->
     true
   | _ -> false
 

compiler/syntax/src/res_token.ml

@@ -106,7 +106,7 @@ let precedence = function
   | BangEqualEqual | LessEqual | GreaterEqual | BarGreater ->
     4
   | Plus | PlusDot | Minus | MinusDot | PlusPlus -> 5
-  | Asterisk | AsteriskDot | Forwardslash | ForwardslashDot -> 6
+  | Asterisk | AsteriskDot | Forwardslash | ForwardslashDot | Percent -> 6
   | Exponentiation -> 7
   | MinusGreater -> 8
   | Dot -> 9

runtime/Pervasives.res

@@ -49,6 +49,7 @@ external \"+": ('a, 'a) => 'a = "%add"
 external \"-": ('a, 'a) => 'a = "%sub"
 external \"*": ('a, 'a) => 'a = "%mul"
 external \"/": ('a, 'a) => 'a = "%div"
+external \"%": ('a, 'a) => 'a = "%mod"
 external mod: ('a, 'a) => 'a = "%mod"
 
 /* Comparisons */

runtime/Pervasives_mini.res

@@ -28,6 +28,7 @@ external \"+": (int, int) => int = "%addint"
 external \"-": (int, int) => int = "%subint"
 external \"*": (int, int) => int = "%mulint"
 external \"/": (int, int) => int = "%divint"
+external \"%": (int, int) => int = "%modint"
 external mod: (int, int) => int = "%modint"
 
 /* Comparisons */

tests/syntax_tests/data/parsing/grammar/expressions/binary.res

@@ -27,6 +27,7 @@ let x = z |> @attr while condition { () }
 
 let x = a + -1 + -2
 let x = a + @attr -1 + @attr -2
+let x = a % a == 0
 
 // should be interpreted as binary expression not prefix op
 let x = a -b

tests/syntax_tests/data/parsing/grammar/expressions/expected/binary.res.txt

@@ -13,6 +13,7 @@ let x = while condition do () done z
 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 - b
 let x = a -. b
 ;;Constructor (a, b)

tests/syntax_tests/data/printer/expr/binary.res

@@ -53,6 +53,7 @@ let () = (x: int) |> (print_int: int => unit)
 // math
 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)

tests/syntax_tests/data/printer/expr/expected/binary.res.txt

@@ -84,6 +84,7 @@ let () = (print_int: int => unit)((x: int))
 // math
 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)

tests/tests/src/belt_int_test.mjs

@@ -35,6 +35,7 @@ Mocha.describe("Belt_int_test", () => {
     Test_utils.eq("File \"belt_int_test.res\", line 40, characters 7-14", -1, -1);
     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);
   });
 });
 

tests/tests/src/belt_int_test.res

@@ -40,5 +40,6 @@ describe(__MODULE__, () => {
     eq(__LOC__, 2 - 3, -1)
     eq(__LOC__, 2 * 3, 6)
     eq(__LOC__, 2 / 3, 0)
+    eq(__LOC__, 2 % 2, 0)
   })
 })

tests/tests/src/unified_ops_test.mjs

@@ -51,6 +51,14 @@ function case2(a, b) {
   return a + "test" + b;
 }
 
+function even(n) {
+  return n % 2 === 0;
+}
+
+function odd(n) {
+  return n % 2 === 1;
+}
+
 let int = 3;
 
 export {
@@ -69,5 +77,7 @@ export {
   rhsstring,
   case1,
   case2,
+  even,
+  odd,
 }
 /* No side effect */

tests/tests/src/unified_ops_test.res

@@ -17,3 +17,6 @@ let rhsstring = (a, b: string) => a + b
 
 let case1 = a => 1 + a
 let case2 = (a, b) => a + "test" + b
+
+let even = n => n % 2 == 0
+let odd = n => n % 2 == 1