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;

}
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.