anchor.diff:    Look inside such a file and we'll see an `export` statement like this one.
   +makeExample('architecture/ts/app/app.component.ts', 'export', 'app/app.component.ts (excerpt)')(format=".")
   :marked
  -  The `export` statement tells TypeScript that is a module whose
  -  `AppComponent` class is public and accessible to other modules of the application
  +  The `export` statement tells TypeScript that this is a module whose
  +  `AppComponent` class is public and accessible to other modules of the application.
     
     When we need a reference to the `AppComponent`, we **import** it like this:
   +makeExample('architecture/ts/app/boot.ts', 'import', 'app/boot.ts (excerpt)')(format=".")
  
positive.code:   that tells Angular how to render the Component.
  
    A template looks like regular HTML much of the time ... and then it gets a bit strange. Here is a
    template for our `HeroList` component
  +makeExample('architecture/ts/app/hero-list.component.html',null,'app/hero-list.component.html')
  :marked
    We recognize `<h2>` and  `<div>`. 
    But there's other markup that no one told us about in school.
    What is`*ngFor`, {{hero.name}}, `(click)`, `[hero]`, and `<hero-detail>`?
    These are examples of Angular's [template syntax](template-syntax.html). 
    We will grow accustomed to that syntax and may even learn to love it.
    We'll begin to explain it in a moment.
  
negative.code:   >**Component Router** - With the Component Router service, users can navigate a multi-screen application 
    in a familiar web browsing style using URLs.
    
    >**Events** - The DOM raises events. So can components and services. Angular offers mechanisms for
    publishing and subscribing to events including an implementation of the [RxJS Observable](https://github.com/zenparsing/es-observable) proposal.
    
    >**[Forms](forms.html)** - Support complex data entry scenarios with HTML-based validation and dirty checking.
  