title: Angular set ng-minlength from controller does not work
body: <p>Here is the controller:</p>
  
  <pre><code>    function Ctrl($scope) {
        $scope.text = 'guest';
        $scope.word = /^\w*$/;
        $scope.min_length = 4;
      }
  </code></pre>
  
  <p>Here is the view:</p>
  
  <pre><code>    &lt;form name="myForm" ng-controller="Ctrl"&gt;
        Single word: 
        &lt;input type="text" name="input" ng-model="text"
               ng-pattern="word" ng-minlength="min_length" required /&gt;
        ...
      &lt;/form&gt;
  </code></pre>
  
  <p>The <code>ng-minlength="min_length"</code> won't trigger the minlength error except I explicitly write
  <code>ng-minlength="4"</code>. However, <code>ng-pattern="word"</code> works fine.</p>
  
  <p>Here is the <a href="http://jsfiddle.net/sliter/uVXn4/" rel="nofollow">jsfiddle</a> link</p>
  
  <p>Is it because I am doing wrong or there is way to get around?</p>