> are they using some subset of the language? They're using a derived language called Hack. > Does the compiled code use a garbage collector? Or reference cou

> are they using some subset of the language? They're using a derived language called Hack. > Does the compiled code use a garbage collector? Or reference counting? Not sure but it's open source so I'm sure you can dig up the answers one way or another: https://github.com/facebook/hhvm https://github.com/facebook/hhvm