As a reverse-engineer tinkering with iOS this reminded me of some system apps.<p>E.g. in the app store you click a button, send a request, receive the response which contains a xml-like structure describing the UI mutation to your action.<p><Alert><p><pre><code> <Header>iTunes Login</Header>
<Body>We could not find a user with those credentials.</Body>
</code></pre>
</Alert><p>type stuff.