title: angular ngRepeat $index in name attribute
body: <pre><code>&lt;div ng-repeat="fod in form.order_details"&gt;
  ...
      &lt;td class="control-cell"&gt;
          &lt;span ng-class="{error: prForm['qty_'+$index].$error.required &amp;&amp; showValidationMessages}"&gt;
              &lt;input type="number" name="{{'qty_' + $index}}" ng-model="fod.qty" ng-change="qtyPerKindCalc($index);" id="{{'qty_' + $index}}" required /&gt;
              &lt;span ng-show="prForm['qty_'+$index].$error.required &amp;&amp; showValidationMessages" class="error-msg"&gt;This field required&lt;/span&gt;
          &lt;/span&gt;
      &lt;/td&gt;
  ...
  &lt;/div&gt;
  </code></pre>
  
  <p>ngRepeat, where i'm have required field. I'm have form object $scope.prForm - where i'm see $error. Problem is in name="{{'qty_' + $index}}". In $scope.prForm i'm have field</p>
  
  <pre><code>{{'qty_' + $index}}: instantiate.c
  </code></pre>
  
  <p>but i'm need</p>
  
  <pre><code>qty_0: instantiate.c
  </code></pre>
  
  <p>How I can have good {{'qty_' + $index}} operation in name attribute?</p>