> I'm proud to release the result of a Facebook-sponsored study on the feasibility of using the RPython toolchain to produce a PHP interpreter. The rules were simple: two months; one person; get as close to PHP as possible, implementing enough warts and corner cases to be reasonably sure that it answers hard problems in the PHP language. The outcome is called Hippy VM and implements most of the PHP 1.0 language (functions, arrays, ints, floats and strings).
HipHop its Facebook sponsored just in time compiler for php. HHVM (Hip Hop Virtual Machine). My understanding is its 95%ish compatible with most php. They're working using framework unit tests to get the percent higher.
http://www.hhvm.com/frameworks/
