Facebook's Hack lang is open source, though not publicly documented. This commit points out a lot of the implementation and test files: https://github.com/faceb

Facebook's Hack lang is open source, though not publicly documented. This commit points out a lot of the implementation and test files: https://github.com/facebook/hhvm/commit/db9577b1409b74293fd91d39455fe7ef3d4d0a7c https://github.com/facebook/hhvm/commit/db9577b1409b74293fd9...