code: function(content, pos, sanitize) {
  			if (sanitize) {
  				content = this.sanitize(content);
  			}
  
  			var skipString = function() {
  				var quote = content.charAt(pos);
  				if (quote == '"' || quote == "'") {
  					while (--pos >= 0) {
  						if (content.charAt(pos) == quote && content.charAt(pos - 1) != '\\') {
  							break;
  						}
  					}
  					return true;
  				}
  
  				return false;
  			};
  
  			// find CSS selector
  			var ch;
  			var endPos = pos;
  			while (--pos >= 0) {
  				if (skipString()) continue;
  
  				ch = content.charAt(pos);
  				if (ch == ')') {
  					// looks like it’s a preprocessor thing,
  					// most likely a mixin arguments list, e.g.
  					// .mixin (@arg1; @arg2) {...}
  					while (--pos >= 0) {
  						if (skipString()) continue;
  
  						if (content.charAt(pos) == '(') {
  							break;
  						}
  					}
  					continue;
  				}
  
  				if (ch == '{' || ch == '}' || ch == ';') {
  					pos++;
  					break;
  				}
  			}
  
  			if (pos < 0) {
  				pos = 0;
  			}
  			
  			var selector = content.substring(pos, endPos);
  
  			// trim whitespace from matched selector
  			var m = selector.replace(reSpace, ' ').match(reSpaceTrim);
  			if (m) {
  				pos += m[1].length;
  				endPos -= m[2].length;
  			}
  
  			return range.create2(pos, endPos);
  		}
docs: Extracts CSS selector from CSS document from
  given position. The selector is located by moving backward
  from given position which means that passed position
  must point to the end of selector
  @param  {String}  content CSS source
  @param  {Number}  pos     Search position
  @param  {Boolean} sanitize Sanitize CSS source before processing.
  Off by default and assumes that CSS must be comment-free already
  (for performance)
  @return {Range}