Facebook wrote a new runtime and has, over time, changed the language rather significantly (eg strong static typing, async/await, generics, overhauled much of t

Facebook wrote a new runtime and has, over time, changed the language rather significantly (eg strong static typing, async/await, generics, overhauled much of the standard library.) It's called Hack. At this point, I don't think you could reasonably say facebook's written in php any more than you could say various c++ projects are written in C. https://hacklang.org/ https://hacklang.org/