HipHop PHP has been a rumored Facebook project for a few months now, finally it’s arrived.

“HipHop transforms your PHP source code into highly optimized C++ and then compiles it with g++ to build binary files. You keep coding in simpler PHP, then HipHop executes your source code in a semantically equivalent manner and sacrifices some rarely used features – such as eval() – in exchange for improved performance.” (more info, repo).

It looks neat (in a Google GWT kind of way), keen to see how it plays with opcode caches, xdebug, shared memory stuff etc. and whether it makes pcntl_fork() actually useful (no eval(); so chances are slim). Facebook has very different requirements to the rest of us and an already highly optimised code base, so HipHop may be filling a very specific niche. Hopefully developers won’t use it as a bandaid to actual performance profiling, or expect it to solve their I/O issues. fingers crossed :p