code: function tokenize() {
  		var ch = walker.ch;
  	
  		if (ch === " " || ch === "\t") {
  			return white();
  		}
  
  		if (ch === '/') {
  			return comment();
  		} 
  
  		if (ch === '"' || ch === "'") {
  			return str();
  		}
  		
  		if (ch === '(') {
  			return brace();
  		}
  	
  		if (ch === '-' || ch === '.' || isDigit(ch)) { // tricky - char: minus (-1px) or dash (-moz-stuff)
  			return num();
  		}
  	
  		if (isNameChar(ch)) {
  			return identifier();
  		}
  
  		if (isOp(ch)) {
  			return op();
  		}
  
  		if (ch === '\r') {
  			if (walker.peek() === '\n') {
  				ch += walker.nextChar();
  			}
  
  			tokener(ch, 'line');
  			walker.nextChar();
  			return;
  		}
  		
  		if (ch === '\n') {
  			tokener(ch, 'line');
  			walker.nextChar();
  			return;
  		}
  		
  		raiseError("Unrecognized character '" + ch + "'");
  	}
docs: call the appropriate handler based on the first character in a token suspect