Phack: HackLang to PHP Transpiler
This project is EXTREMELY EXPERIMENTAL and not ready for prime-time.
Only a few HackLang features are supported at this time, and they aren't fully tested.
What is this?
This project is an attempt to make HackLang code run "out of the box" on a regular PHP runtime without the need for a custom extension (it's all PHP code!). By supporting all of HackLang's rich typing system, we'll be able to make use of the static typechecker to perform robust analysis while still executing it on the stable and trusted PHP runtime.
Any attempt to use HackLang files which have not passed
hh_client is a terrible mistake, and you should feel bad.
How does it work?
Phack extends PHP-Parser by amending the PHP 7 parsing rules and overriding the Lexer's pre/post processor hooks. This produces a usable AST, which can then be "PrettyPrinted" into normal PHP. The following table shows our roadmap:
|Short Lambdas||Alpha||Needs more tests|
|Generics||Alpha||Partial type erasure for PHP compat (base type preserved)|
|XHP||TBD||XHP-1.x support available through https://www.github.com/phplang/xhp for now, XHP-2.x coming with this library|
|Enums||Alpha||Need to actually implement \InvariantException for full HackLang compat...|
|Pipe Op||Alpha||Limited to one use of lhs in rhs (unlike HackLang)|
|Constructor Parameter Promotion||Alpha|
|Prop/Const Typing||Alpha||Props: Yes, Consts: No|
|Soft/Nullable typing||Alpha||Full erasure on soft/nullables. Need logging for soft, and need psuedo statements for nullable checking (or PHP 7.1 nullable type support)|
|User Attributes||Alpha||UA erasure, need to preserve somewhere for reflection.|
|Collections||TBD||Static initialization is... complicated...|
|Async||Unlikely||PHP's Engine just doesn't support this concept well|
|Trailing Commas||Alpha||Allow trailing comma in arg/param lists|
How do I use it?
To include a HackLang file manually, use
\PhpLang\Phack\includeFile() as you would use
include, similarly you can use
\PhpLang\Phack\evalString as you would
To have composer handle HackLang files transparently, you can try out the EXPERIMENTAL replacement
ClassLoader by invoking, at the top level of your entrypoint:
\PhpLang\Phack\ClassLoader::hijack();. After this point, any class autoloaded via composer will be preprocessed from HackLang into runable PHP.
To see how HackLang files transpile to PHP, you can run
vendor/bin/phack which will invoke
PhpLang\Phack\transpileString for you and provide the output.