slim - I'm getting back into PHP however the below syntax is escaping me

one text

Solution:

require() is an include() that fails if the file cannot be included.

If the included PHP file ends with a return statement, it will return this value to the caller.

In your case, it looks like bootstrap.php returns an object with a run() method.

Note that require() is not actually a function but a language construct, so the parentheses are optional; these 2 lines are therefore equivalent:

require('script.php');

require 'script.php';