title: how to set an interpolated value in angular directive?
body: <p>How do I set the interpolated value in a directive?  I can read the correct value from the following code, but I have not been able to set it.</p>
  
  <p><strong>js:</strong></p>
  
  <pre class="lang-js prettyprint-override"><code>app.directive('ngMyDirective', function () {
      return function(scope, element, attrs) {
          console.log(scope.$eval(attrs.ngMyDirective));
  
          //set the interpolated attrs.ngMyDirective value somehow!!!
      }
  });
  </code></pre>
  
  <p><strong>html:</strong></p>
  
  <pre class="lang-js prettyprint-override"><code>&lt;div ng-my-directive="myscopevalue"&gt;&lt;/div&gt;
  </code></pre>
  
  <p>where <code>myscopevalue</code> is a value on my controller's scope.</p>