"Also what about windows users, still a very significant portion of the PHP user base?"
Yes, especially during development. I am toying w/ a PHP implementation on top of luajit, written in PHP so it may be more hackable and bootstrapped.
The real problem is PHP fails to define a specification that implementations can follow (though they probably weren't prepared for the current situation). Sadly the runtime becomes the spec, and with such a large standard library, it's hard to predict what happens in dynamic languages when you send in something undocumented. In order to work w/ the myriad of PHP projects out there, unfortunately you have to mimic the undefined aspects.
We are headed towards a more fragmented PHP than we already have. I've had enough problems changing PHP versions (regressions and undefined standard function changes), now with HHVM, you will have one more fragmentation piece. I'm all for different implementations. The saving grace I've found is all the language phpt files (but doesn't help w/ parsing and many compile-time errors).
Do you have a blog, or do you intend to put it on Github?
A PHP parser written in PHP that generates bytecode for LuaJIT or HHVM's JIT-runtime would be cool. I was thinking about this too. And it would be fun to hack around :)
Yes, especially during development. I am toying w/ a PHP implementation on top of luajit, written in PHP so it may be more hackable and bootstrapped.
The real problem is PHP fails to define a specification that implementations can follow (though they probably weren't prepared for the current situation). Sadly the runtime becomes the spec, and with such a large standard library, it's hard to predict what happens in dynamic languages when you send in something undocumented. In order to work w/ the myriad of PHP projects out there, unfortunately you have to mimic the undefined aspects.
We are headed towards a more fragmented PHP than we already have. I've had enough problems changing PHP versions (regressions and undefined standard function changes), now with HHVM, you will have one more fragmentation piece. I'm all for different implementations. The saving grace I've found is all the language phpt files (but doesn't help w/ parsing and many compile-time errors).