Sounds like it's better than I thought. > I'm not sure I understand your argument here. Hack was designed to be seamlessly used in a mixed PHP/Hack codebase.

Sounds like it's better than I thought. > I'm not sure I understand your argument here. Hack was designed to be seamlessly used in a mixed PHP/Hack codebase. My argument is that if another person/organization implemented a Hack runtime it'd most likely be Hack-only, not Hack + PHP. As you can see, I don't mean in HHVM itself but in potential 3rd party implementations. So software written to run in a mixed Hack mode now, may not be supported in the future with other interpreters. I'm still interested in trying Hack, in spite of that opinion.