The ability to statically type in the most recent version of HHVM, via their internally developed Hack “language”. Hack is a derivate of PHP, but supports stati

The ability to statically type in the most recent version of HHVM, via their internally developed Hack “language”. Hack is a derivate of PHP, but supports static typing. You start files you want to type check before compilation with <?hh instead of <?php, and the compiler does the rest. This approach further increases the quality of compilation, making native code that much more efficient, and HHVM’s PHP that much faster.