controller_syntax.php

<?php

class PostsController {
  public function show($params) { // Note that you have to accept an argument here to get param information
    $post = Post.find($params['id']); // This param comes from the identifier we set in the route.  Note that the `Post.find` is a fictional method

    include 'views/posts/show.php';
  }

  public function index($params) {
    // Format data is available!  However, this only operates based on the content_type provided, and not by the format of the URL
    if($params['format'] === 'json') {
      include 'views/posts/index.json.php';
    } else {
      include 'views/posts/index.php';
    }
  }
}