Simple lexical analysis for a JavaScript expression. Written as a prototype for pre-parsing JavaScript bindings (Epoxy.js). Will alphabetically sort the order of object property lists while removing all non-string whitespace. Example expression: 'text: all("a", "x", "c"), css:{fontWeight:"bold", color:["#f00, \\"#fee", "#00f"]}, html:firstName'

expression-parser

function parseBindings(bindings, sorted) {
	var attrs = [];
	var token = '';
	bindings += ',';

	for (var i = 0, len = bindings.length; i < len; i++) {
		var c = bindings.charAt(i);

		// Comma: chunk off tokens at list delimiter.
		if (c == ',') {
			attrs.push(token);
			token = '';
			continue;
		}
		
		// Space: skip whitespace.
		if (c == ' ') {
			continue;
		}
		
		// String: open at quote character, close at unescaped match.
		if (c == "'" || c == '"') {
			var string = '';
			for (i = i+1; i < len; i++) {
				var q = bindings.charAt(i);
				if (q == c) break;
				if (q == '\\') q = bindings.charAt(i+=1);
				string += q;
			}
			c = c + string + c;
		}
		// Block: chunk out block scope and parse it.
		else if (c == '{' || c == '[' || c == '(') {
			var opener = c;
			var closer = c == '{' ? '}' : c == '[' ? ']' : ')';
			var io = i;
			var ic = i;
			while (io >= i && io <= ic) {
				io = bindings.indexOf(opener, io+1);
				ic = bindings.indexOf(closer, ic+1);
			}
			c = opener + parseBindings(bindings.slice(i+1, ic), c == '{') + closer;
			i = ic;
		}

		token += c;
	}

	if (sorted) attrs.sort();
	return attrs.join(',');
}