PHP right-associative operator ** denoting exponentiation (two multiplications)

A right-associative operator ** was added to denote exponentiation. The short syntax ** = is also available.

<? php
printf ("2 ** 3 ==% d \ n", 2 ** 3);
printf ("2 ** 3 ** 2 ==% d \ n", 2 ** 3 ** 2);

$ a = 2;
$ a ** = 3;
printf ("a ==% d \ n", $ a);
?>

The result of this example:

 2 ** 3 == 8
 2 ** 3 ** 2 == 512
 a == 8