I found it for its Datalog implementation.

https://en.wikipedia.org/wiki/Datalog and http://www.learndatalogtoday.org/.

Thesis URL: https://tspace.library.utoronto.ca/handle/1807/80713

Aaw, this would have been great if it didn't use `eval`, but just executed `+`, `-` etc directly.

It doesn't use the built-in eval(). There's a local function in the code named "eval" that executes the operation -- not the best choice of names, really.

Oops, guess I read it a bit too fast.