title: ng-pattern gives "Lexer Error"?
body: <p>As an attribute of an input element I have:</p>
  
  <pre><code>ng-pattern="^\d{5}(?:[-\s]\d{4})?$"
  </code></pre>
  
  <p>Whats wrong this this expression?</p>
  
  <p>I get this error:</p>
  
  <pre><code>Lexer Error: Unexpected next character  at columns 0-0 [^] in expression [^\d{5}(?:[-\s]\d{4})?$].
  </code></pre>