title: How to interact with isolate scope variable within a directive controller?
body: <p>I have directive myDirective, that has an two-way binding isolate scope.  When the user clicks a button, I want to change the isolate scope to be a value.  I thought isolate scopes were bound to the $scope, but I am wrong.  How do I 'grab' and interact with that isolate scope?  Are they not attached to the directive controller's scope?</p>
  
  <pre><code>angular.module("app", [])
  .controller("myCtrl", function($scope){
      $scope.ctrlTwoway = "Eggs";
  })
  .directive("myDirective", function(){
      return {
          scope: {
            twoway: =
          },
          template: "&lt;button ng-click="changeTwoway()"&gt;Change two way isolate scope&lt;/button&gt;",
          controller: function($scope, $element, $attrs){
              $scope.changeTwoway = function(){
                  // get twoway from isolate scope, and update the value with "bacon"
                  // $scope.twoway = "bacon" doesn't work 
                  // nor does $attrs.twoway = "bacon" work, either :(
              };
          }
      }
  });
  </code></pre>
  
  <p>And the HTML</p>
  
  <pre><code>...
  &lt;div my-directive twoway="{{ctrlTwoway}}"&gt;&lt;/div&gt;
  Current value: {{ctrlTwoway}}
  </code></pre>