gistfile1.js

  extend: function(ext) {
    var ret = SC.mixin(SC.beget(this), ext),
        key, value, cur;
    
    for(key in ret) {
      value = ret[key];
      if (value instanceof Function && !value.superclass && (value !== (cur=this[key]))) {
        value.superclass = value.base = cur;
      }
    }
    
    return ret;
  }