Shorthand syntax for PHP arrays

Question

Is this valid PHP syntax or just a shorthand for the documentation? Does anybody have the link to a help page describing this notation?

$array = [
  [1, 2],
  [3, 4],
];

If you have a look at the code examples in the Unpacking nested arrays with list() section on the foreach help page you will see this possibly new notation, however I can't seem to find any help for this.

Answer 1

The new syntax [] was added in PHP 5.4.0. Check out the documentation on arrays