Facebook unveils 'Hack' a new PHP based programming language

Facebook is at it again, introducing a new programming language designed to make the process of writing and testing code faster. Called Hack, it has been in use for a year at the social networking company, and on Thursday Facebook released it as open source.

Hack is designed to combine the fast development cycle of PHP with the static typing of languages such as Java. The result is a landmark gradually typed language where dynamic and static code interoperate.

“Traditionally, dynamically typed languages allow for rapid development but sacrifice the ability to catch errors early and introspect code quickly, particularly on larger codebases,” wrote Facebook software engineers Alok Menghrajani and Julien Verlaguet. “Conversely, statically typed languages provide more of a safety net, but often at the cost of quick iteration.
“We believed there had to be a sweet spot. Thus, Hack was born. We believe that it offers the best of both dynamically typed and statically typed languages, and that it will be valuable to projects of all sizes.”

Hack was developed for the HipHop Virtual Machine (HHVM), the PHP virtual machine Facebook created in 2013 to face the strain of running the massive amounts of PHP code on an expanding number of servers. Facebook was built in 2003 in PHP, but as millions of users joined the social network, the dynamically typed language began to show its limitations.

HHVM was Facebook’s first step in evolving its codebase for the future of Web development, and Hack is supposed to finish the job. Facebook is hosting a Hack-related event at its campus next month.