title: Angular 2: Is usage of Parentheses / Square brackets mandatory?
body: <p>In the Angular 2 previews released so far, the syntax of the markup has been modified from <code>ng-</code> prefixes to square parentheses and square brackets.</p>
  
  <p>Whereas before one would have:</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;input ng-model="userName" /&gt;
  &lt;button ng-click="btnClick()"&gt;Run&lt;/button&gt;
  </code></pre>
  
  <p>The new syntax is:</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;input [value]="userName" /&gt;
  &lt;button (click)="btnClick()"&gt;Run&lt;/button&gt;
  </code></pre>
  
  <p>Does anybody know if this syntax is/will be mandatory, and without alternatives?</p>
  
  <p>We currently have an application in which the HTML is generated through XSLT, and <code>[</code> and <code>(</code> are not valid attributes - thereby being unable to generate Angular 2 JS syntax.</p>