code: function(name) {
        var pos = name.indexOf(".");
        if (pos > -1) {
          name = name.substring(0, pos); 
        }
        for (var tmp = this.__scope; tmp; tmp = tmp.parent) {
          if (tmp.vars[name] !== undefined) {
            return true; 
          } 
        }
        return false;
      }
docs: Tests whether there is a variable declaration accessible to the current
  scope, ie including parent scope
  
  @param name
  @returns {Boolean}