code: function PropertyName(text, hack, line, col) {
  
      SyntaxUnit.call(this, text, line, col, Parser.PROPERTY_NAME_TYPE);
  
      /**
       * The type of IE hack applied ("*", "_", or null).
       * @type String
       * @property hack
       */
      this.hack = hack;
  
  }
docs: Represents a selector combinator (whitespace, +, >).
  @namespace parserlib.css
  @class PropertyName
  @extends parserlib.util.SyntaxUnit
  @constructor
  @param {String} text The text representation of the unit.
  @param {String} hack The type of IE hack applied ("*", "_", or null).
  @param {int} line The line of text on which the unit resides.
  @param {int} col The column of text on which the unit resides.