Add support for CSS3 calc

Author: raxbg

lib/Sabberworm/CSS/Parser.php

@@ -434,6 +434,8 @@ private function parsePrimitiveValue() {
 			$oValue = $this->parseColorValue();
 		} else if ($this->comes('url', true)) {
 			$oValue = $this->parseURLValue();
+		} else if ($this->comes('calc', true) || $this->comes('-webkit-calc', true)) {
+			$oValue = $this->parseCalcValue();
 		} else if ($this->comes("'") || $this->comes('"')) {
 			$oValue = $this->parseStringValue();
 		} else if ($this->comes("progid:") && $this->oParserSettings->bLenientParsing) {
@@ -520,6 +522,15 @@ private function parseURLValue() {
 		return $oResult;
 	}
 
+	private function parseCalcValue() {
+		$func = $this->comes('calc', true) ? 'calc' : '-webkit-calc';
+		$this->consume($func);
+		$this->consumeWhiteSpace();
+		$this->consume('(');
+		$aArguments = $this->parseValue(array('+', '-', '*', '/', ' '));
+		return new CSSFunction($func, $aArguments, ',', $this->iLineNo);
+	}
+
 	/**
 	 * Tests an identifier for a given value. Since identifiers are all keywords, they can be vendor-prefixed. We need to check for these versions too.
 	 */

tests/Sabberworm/CSS/ParserTest.php

@@ -387,6 +387,13 @@ function testUrlInFile() {
 		$this->assertSame($sExpected, $oDoc->render());
 	}
 
+	function testCalcInFile() {
+		$oDoc = $this->parsedStructureForFile('calc', Settings::create()->withMultibyteSupport(true));
+		$sExpected = 'div {width: calc(100%/4);}
+div {height: -webkit-calc(9/16*100%);}';
+		$this->assertSame($sExpected, $oDoc->render());
+	}
+
 	function testUrlInFileMbOff() {
 		$oDoc = $this->parsedStructureForFile('url', Settings::create()->withMultibyteSupport(false));
 		$sExpected = 'body {background: #fff url("http://somesite.com/images/someimage.gif") repeat top center;}

tests/files/calc.css

@@ -0,0 +1,4 @@
+div { width: calc(100% / 4); }
+div {
+	height: -webkit-calc(9/16 * 100%);
+}