This directory is for the Num implemenation based on Nim.
Nim is a statically typed language which compiles to C (as well as JS), which makes interoperability with C a breeze. It is mostly imperative, but has a lot of features that allow a functional style of programming where appropriate. I think that the feature that defines it mostly is the reliance on compile time metaprogramming, in the LISP tradition. Above all, Nim is very high-level, while still mantaining complete control over memory, much as one would expect from C.
To learn about Nim: http://rnduja.github.io/2015/10/21/scientific-nim/