Stephan Hochdörfer has a quick new post to his site today showing how he was able to setup a Silex-based application to run on the HHVM (HipHopVM) from Facebook.
First of all I assume you already got HHVM running with nginx. If this is not the case feel free to follow these steps to get everything up and running. To install Silex we will use Composer, so let`s install all the needed requirements and Composer itself.
He includes all the commands you'll need to get the Composer dependencies installed (curl, git, unzip) and to pull it down and move it to the right location post-install. He adds a line to his ".bashrc" to enable it for HHVM and creates the sample "composer.json" for the Silex install. Finally, he includes the updates to make to the nginx configuration to handle the needed redirects to the Silex front controller.