Bug fix in calc parsing when the first operand is a negative value

lib/Sabberworm/CSS/Parser.php

@@ -555,34 +555,39 @@ private function parseURLValue() {
 	}
 
 	private function parseCalcValue() {
-		$aOperators = array('+', '-', '*', '/', '(', ')');
+		$aOperators = array('+', '-', '*', '/');
 		$sFunction = trim($this->consumeUntil('(', false, true));
 		$oCalcList = new CalcRuleValueList($this->iLineNo);
 		$oList = new RuleValueList(',', $this->iLineNo);
 		$iNestingLevel = 0;
 		$iLastComponentType = NULL;
 		while(!$this->comes(')') || $iNestingLevel > 0) {
 			$this->consumeWhiteSpace();
-			if (in_array($this->peek(), $aOperators)) {
-				if (($this->comes('-') || $this->comes('+'))) {
-					if ($this->peek(1, -1) != ' ' || !($this->comes('- ') || $this->comes('+ '))) {
-						throw new UnexpectedTokenException(" {$this->peek()} ", $this->peek(1, -1) . $this->peek(2), 'literal', $this->iLineNo);
-					}
-				} else if ($this->comes('(')) {
-					$iNestingLevel++;
-				} else if ($this->comes(')')) {
-					$iNestingLevel--;
-				}
+			if ($this->comes('(')) {
+				$iNestingLevel++;
 				$oCalcList->addListComponent($this->consume(1));
-				$iLastComponentType = CalcFunction::T_OPERATOR;
-			} else {
+				continue;
+			} else if ($this->comes(')')) {
+				$iNestingLevel--;
+				$oCalcList->addListComponent($this->consume(1));
+				continue;
+			}
+			if ($iLastComponentType != CalcFunction::T_OPERAND) {
 				$oVal = $this->parsePrimitiveValue();
-				if ($iLastComponentType == CalcFunction::T_OPERAND) {
-					throw new UnexpectedTokenException(sprintf('Next token was expected to be an operand of type %s. Instead "%s" was found.', implode(', ', $aOperators), $oVal), '', 'custom', $this->iLineNo);
-				}
-
 				$oCalcList->addListComponent($oVal);
 				$iLastComponentType = CalcFunction::T_OPERAND;
+			} else {
+				if (in_array($this->peek(), $aOperators)) {
+					if (($this->comes('-') || $this->comes('+'))) {
+						if ($this->peek(1, -1) != ' ' || !($this->comes('- ') || $this->comes('+ '))) {
+							throw new UnexpectedTokenException(" {$this->peek()} ", $this->peek(1, -1) . $this->peek(2), 'literal', $this->iLineNo);
+						}
+					}
+					$oCalcList->addListComponent($this->consume(1));
+					$iLastComponentType = CalcFunction::T_OPERATOR;
+				} else {
+					throw new UnexpectedTokenException(sprintf('Next token was expected to be an operand of type %s. Instead "%s" was found.', implode(', ', $aOperators), $oVal), '', 'custom', $this->iLineNo);
+				}
 			}
 		}
 		$oList->addListComponent($oCalcList);

tests/Sabberworm/CSS/ParserTest.php

@@ -390,10 +390,17 @@ function testUrlInFile() {
 	function testCalcInFile() {
 		$oDoc = $this->parsedStructureForFile('calc', Settings::create()->withMultibyteSupport(true));
 		$sExpected = 'div {width: calc(100% / 4);}
+div {margin-top: calc(-120% - 4px);}
 div {height: -webkit-calc(9 / 16 * 100%) !important;width: -moz-calc(( 50px - 50% ) * 2);}';
 		$this->assertSame($sExpected, $oDoc->render());
 	}
 
+	function testCalcNestedInFile() {
+		$oDoc = $this->parsedStructureForFile('calc-nested', Settings::create()->withMultibyteSupport(true));
+		$sExpected = '.test {font-size: calc(( 3 * 4px ) + -2px);top: calc(200px - calc(20 * 3px));}';
+		$this->assertSame($sExpected, $oDoc->render());
+	}
+
 	function testGridLineNameInFile() {
 		$oDoc = $this->parsedStructureForFile('grid-linename', Settings::create()->withMultibyteSupport(true));
 		$sExpected = "div {grid-template-columns: [linename] 100px;}\nspan {grid-template-columns: [linename1 linename2] 100px;}";

tests/files/calc-nested.css

@@ -0,0 +1,4 @@
+.test {
+  font-size: calc((3 * 4px) + -2px);
+  top: calc(200px - calc(20 * 3px));
+}

tests/files/calc.css

@@ -1,4 +1,5 @@
 div { width: calc(100% / 4); }
+div { margin-top: calc(-120% - 4px); }
 div {
 	height: -webkit-calc(9/16 * 100%)!important;
 	width: -moz-calc((50px - 50%)*2);