fix: allow parentheses around the exponent in the unit parser (unit(\m ^ (1)\))

HISTORY.md

@@ -2,6 +2,7 @@
 
 # unpublished changes since 15.2.0
 
+- Fix: #3620 allow parentheses around exponents in unit parsing.
 - Docs: fix the browser example `rocket_trajectory_optimization.html` (#3654).
   Thanks @dvd101x.
 

src/type/unit/Unit.js

@@ -357,11 +357,24 @@ export const createUnitClass = /* #__PURE__ */ factory(name, dependencies, ({
       skipWhitespace()
       if (parseCharacter('^')) {
         skipWhitespace()
+        const hasParentheses = parseCharacter('(')
+        if (hasParentheses) {
+          skipWhitespace()
+        }
+
         const p = parseNumber()
         if (p === null) {
           // No valid number found for the power!
           throw new SyntaxError('In "' + str + '", "^" must be followed by a floating-point number')
         }
+
+        if (hasParentheses) {
+          skipWhitespace()
+          if (!parseCharacter(')')) {
+            throw new SyntaxError('Unmatched "(" in "' + text + '"')
+          }
+        }
+
         power *= p
       }
 

test/unit-tests/type/unit/Unit.test.js

@@ -915,6 +915,33 @@ describe('Unit', function () {
       assert.strictEqual(unit1.units[0].power, 1)
     })
 
+    it('should parse units with parenthesized powers correctly', function () {
+      let unit1 = math.unit('m ^ (1)')
+      assert.strictEqual(unit1.equals(math.unit('m')), true)
+      assert.strictEqual(unit1.units[0].unit.name, 'm')
+      assert.strictEqual(unit1.units[0].power, 1)
+
+      unit1 = Unit.parse('m^(-2)')
+      assert.strictEqual(unit1.units[0].unit.name, 'm')
+      assert.strictEqual(unit1.units[0].power, -2)
+
+      unit1 = Unit.parse('s^(0.5)')
+      assert.strictEqual(unit1.units[0].unit.name, 's')
+      assert.strictEqual(unit1.units[0].power, 0.5)
+
+      unit1 = Unit.parse('m ^ ( 2 )')
+      assert.strictEqual(unit1.units[0].unit.name, 'm')
+      assert.strictEqual(unit1.units[0].power, 2)
+
+      unit1 = Unit.parse('m^2')
+      assert.strictEqual(unit1.units[0].unit.name, 'm')
+      assert.strictEqual(unit1.units[0].power, 2)
+
+      unit1 = Unit.parse('m^-2')
+      assert.strictEqual(unit1.units[0].unit.name, 'm')
+      assert.strictEqual(unit1.units[0].power, -2)
+    })
+
     it('should parse expressions with nested parentheses correctly', function () {
       let unit1 = Unit.parse('8.314 kg (m^2 / (s^2 / (K^-1 / mol)))')
       approxEqual(unit1.value, 8.314)
@@ -975,6 +1002,8 @@ describe('Unit', function () {
       assert.throws(function () { Unit.parse('/meter') }, /Unexpected "\/"/)
       assert.throws(function () { Unit.parse('1 */ s') }, /Unexpected "\/"/)
       assert.throws(function () { Unit.parse('45 kg 34 m') }, /Unexpected "3"/)
+      assert.throws(function () { Unit.parse('m^()') }, SyntaxError)
+      assert.throws(function () { Unit.parse('m^(2') }, SyntaxError)
     })
 
     it('should throw an exception when parsing an invalid type of argument', function () {