[luminati]

IIRC the author has a PhD in CS, and his thesis work was on PLT.

[ook]

http://www.tara.tcd.ie/handle/2262/77562 - "Design and implementation of an ahead-of-time compiler for PHP" is the PhD thesis in question.

A google tech talk related to this work is on youtube https://www.youtube.com/watch?v=kKySEUrP7LA

You can find multiple other papers on google scholar where Paul was an author all related to programming languages, compilers etc.

[mlindner]

Some people are much better with theory than the application of that theory. I've met a lot of theory people that just care about implementing something that does something to get the result they want rather than the nitty gritty of making things efficient.