dist/picturefill.js
function parseComponentValues(str) {
			var chrctr;
			var component = "";
			var componentArray = [];
			var listArray = [];
			var parenDepth = 0;
			var pos = 0;
			var inComment = false;

			function pushComponent() {
				if (component) {
					componentArray.push(component);
					component = "";
				}
			}

			function pushComponentArray() {
				if (componentArray[0]) {
					listArray.push(componentArray);
					componentArray = [];
				}
			}

			// (Loop forwards from the beginning of the string.)
			while (true) {
				chrctr = str.charAt(pos);

				if (chrctr === "") { // ( End of string reached.)
					pushComponent();
					pushComponentArray();
					return listArray;
				} else if (inComment) {
					if ((chrctr === "*") && (str[pos + 1] === "/")) { // (At end of a comment.)
						inComment = false;
						pos += 2;
						pushComponent();
						continue;
					} else {
						pos += 1; // (Skip all characters inside comments.)
						continue;
					}
				} else if (isSpace(chrctr)) {
					// (If previous character in loop was also a space, or if
					// at the beginning of the string, do not add space char to
					// component.)
					if ( (str.charAt(pos - 1) && isSpace( str.charAt(pos - 1) ) ) || !component ) {
						pos += 1;
						continue;
					} else if (parenDepth === 0) {
						pushComponent();
						pos +=1;
						continue;
					} else {
						// (Replace any space character with a plain space for legibility.)
						chrctr = " ";
					}
				} else if (chrctr === "(") {
					parenDepth += 1;
				} else if (chrctr === ")") {
					parenDepth -= 1;
				} else if (chrctr === ",") {
					pushComponent();
					pushComponentArray();
					pos += 1;
					continue;
				} else if ( (chrctr === "/") && (str.charAt(pos + 1) === "*") ) {
					inComment = true;
					pos += 2;
					continue;
				}

				component = component + chrctr;
				pos += 1;
			}
		}
function parseComponentValues(str) {
			var chrctr;
			var component = "";
			var componentArray = [];
			var listArray = [];
			var parenDepth = 0;
			var pos = 0;
			var inComment = false;

			function pushComponent() {
				if (component) {
					componentArray.push(component);
					component = "";
				}
			}

			function pushComponentArray() {
				if (componentArray[0]) {
					listArray.push(componentArray);
					componentArray = [];
				}
			}

			// (Loop forwards from the beginning of the string.)
			while (true) {
				chrctr = str.charAt(pos);

				if (chrctr === "") { // ( End of string reached.)
					pushComponent();
					pushComponentArray();
					return listArray;
				} else if (inComment) {
					if ((chrctr === "*") && (str[pos + 1] === "/")) { // (At end of a comment.)
						inComment = false;
						pos += 2;
						pushComponent();
						continue;
					} else {
						pos += 1; // (Skip all characters inside comments.)
						continue;
					}
				} else if (isSpace(chrctr)) {
					// (If previous character in loop was also a space, or if
					// at the beginning of the string, do not add space char to
					// component.)
					if ( (str.charAt(pos - 1) && isSpace( str.charAt(pos - 1) ) ) || !component ) {
						pos += 1;
						continue;
					} else if (parenDepth === 0) {
						pushComponent();
						pos +=1;
						continue;
					} else {
						// (Replace any space character with a plain space for legibility.)
						chrctr = " ";
					}
				} else if (chrctr === "(") {
					parenDepth += 1;
				} else if (chrctr === ")") {
					parenDepth -= 1;
				} else if (chrctr === ",") {
					pushComponent();
					pushComponentArray();
					pos += 1;
					continue;
				} else if ( (chrctr === "/") && (str.charAt(pos + 1) === "*") ) {
					inComment = true;
					pos += 2;
					continue;
				}

				component = component + chrctr;
				pos += 1;
			}
		}
(Toy CSS parser. The goals here are: 1) expansive test coverage without the weight of a full CSS parser. 2) Avoiding regex wherever convenient. Quick tests: http://jsfiddle.net/gtntL4gr/3/ Returns an array of arrays.)