This repo contains the Hack Language Specification, a modified version of the PHP specification. It is no longer maintained and does not reflect the current version of Hack.
The easiest way to navigate the specification is via the table of contents.
The latest official release of the specification is 1.1.
You can run the specification tests with HHVM via its
test runner and the
Hack typechecker via hh_client.
Pull requests, issue filings and comments are extremely welcome.
Make sure you understand the contribution process.