Some time ago, I saw that CERN people had their own clang tree with a few addons, most notable one being the C++ REPL (C++ interpreter) called cling.

Now we had a presentation by Pere Mato from CERN who talked about their ROOT data analysis framework. It seems like a really nice and powerful piece of software.

The software is around 50 million lines of code, mostly C++. Some of it is python, but it is only used for quick-and-dirty testing of new ideas.

(C) Pere Mato

Another cool thing is that they use Qt for writing UIs, and that they also run Linux and KDE Plasma.

(C) Pere Mato