Unlike the OP, Nikita's PHP parser is actually used for a lot of things. He wrote a script to detect code broken by syntax changes in the next version of PHP, for example.

Anthony Ferrara used it to implement PHP in PHP: https://github.com/ircmaxell/PHPPHP

nikic and Anthony are some of my favourite PHP developers. The stuff that people have been doing in PHP, what with HHVM and Hack and the PSR standards and Composer/Packagist, etc etc. is just amazing!

^ Wow is all I have to say. Solving PHP's grammatical syntax issues alone is a big thing, I commend efforts like this, it seems to work pretty well too (based on playing around with it for a few minutes).