title: AngularJS - $parse.assign returns not a function error for the string which contain '-'
body: <p>I created an angularjs variable parsing example and it works perfectly in my environment. Below highlighting the code of my implementation</p>
  
  <pre><code>var model = $parse("ABC_DEF");
  model.assign($scope, chart); //Works successfully
  </code></pre>
  
  <p>But here i just changed the variable name to "ABC-DEF". Then  i implement the variable to the same code of above, but here it shows the exception like <code>assign is not a function in $parse</code>. Below showing the error throwing line of codes</p>
  
  <pre><code>var model = $parse("ABC-DEF");
  model.assign($scope, chart); //Not Working- shows assign not a function
  </code></pre>
  
  <p>What is the reason of this issue?</p>