anchor.diff:    * [Local template variables](#local-vars)
     * [Input and output properties](#inputs-outputs)
     * [Template expression operators](#expression-operators)
  +    * [pipe](#pipe)
  +    * ["elvis" (?.)](#elvis)  
   // #enddocregion intro
  -
  -:marked
  -  [Run the live example](/resources/live-examples/template-syntax/ts/plnkr.html)
  -
  +.l-sub-section
  +  :marked
  +    The [live example](/resources/live-examples/template-syntax/ts/plnkr.html) 
  +    demonstrates all of the syntax and code snippets described in this chapter.
  +  
   // #docregion html-1
   .l-main-section
   :marked
  
positive.code:   <a id="elvis"></a>
    ### The Elvis operator ( ?. ) and null property paths
  
    The Angular **Elvis operator (`?.`)** is a fluent and convenient way to guard against null and undefined values in property paths.
    Here it is, protecting against a view render failure if the `currentHero` is null.
  // #enddocregion expression-operators-elvis-1
  +makeExample('template-syntax/ts/app/app.component.html', 'elvis-2')(format=".")
  
negative.code: 
    Many of us are familiar with the component/template duality from our experience with model-view-controller (MVC) or model-view-viewmodel (MVVM). In Angular,  the component plays the part of the controller/viewmodel, and the template represents the view.
  
    Let’s find out what it takes to write a template for our view. We’ll cover these basic elements of template syntax.
  
    # Table Of Contents
  
    * [HTML](#html)
    * [Interpolation](#interpolation)
  