Hack: a new programming language for HHVM

Expect "Why I migrated from Go to Hack" articles soon enough.

Either way, the name is very fitting. I have no use for this, but good for Facebook that they've managed to (at least to some extent) evade some of the many PHP pitfalls.

Because perfect is not the enemy of the good? Because "build atop a crumbling foundation" has demonstrated time and again to be, by far, the most successful way to accomplish anything in computing? Unless you have some example of perfect, now dominant, technologies that have been created ex nihilo that I'm missing? I mean we (facebook) are still using PHP and MySql, improving both. And when we need to break things out, we head into C++, the queen mother of castles on broken foundations.

> But at the same time, layering FP with a home rolled static type checking server (??) is bug prone and is certainly yak shaving (which they have time and money to do). Now they've written (1) a compiler to C++, (2) a compiler to VM byte code, (3) a corresponding runtime for each, (4) extensions to PHP, (5) a type checker, and (6) an inference engine. That's a lot of stuff.

All languages, runtimes, and standard libraries (and databases, and source control, and on and on) are "broken" at sufficient scale. You're going to be spending time rebuilding things other people take for granted no matter who you are and what language and technology you are working in. The underlying assumption that a "proper language" gives you these things for free is completely false.

> Writing correct type checkers and inference engines is kind of difficult.

Just so we are clear, you ask why Facebook didn't rewrite 10,000 human-years of code into a mythical unnamed "proper" language, but you consider writing a type checker to be "difficult". I think you might have vastly inaccurate pictures of what is and isn't "difficult".

> That way, the compiler is now almost an engine to prove your code is correct. I don't see how the same guarantee can be made with something that is just cobbled together.

Computing history is littered with dead projects from people who believed that anything less than perfect is unworkable or non-valuable.

a) try your new code by saving in your editor, and hitting reload in your web browser.

b) it's very approachable. People who only know HTML and CSS can be expected to do a little bit of PHP work to integrate their changes. If you setup the right network mounts, they just need to edit files and reload (see a)

c) it's not super high overhead at runtime. If you're not using a framework, and you don't build up a crazy object hierarchy, it's not too hard to get your page out with about 10 ms of overhead beyond data fetching. For very simple webservices (fetch data, possibly from multiple sources, and do a little formatting for the consumer), I was able to get the overhead down to 2ms. You can certainly do better with other languages, but you can usually get better throughput improvement by working on getting data quickly. Btw, all the frameworks are terrible; many of them add 100 ms to the page just for the privilege of loading the includes; PHP is a framework for web programming thank you very much.

d) cleanup; you don't have to worry about it. If you don't do anything weird (c extensions, with non-preferred malloc), at the end of the request, everything is thrown away.

That said, there are plenty of things PHP isn't good at: I wouldn't run a long running process in PHP; and multithreaded PHP sounds like a bad idea.