Julia feels like a scripting language but every function is effectively a template. I prototype lots of high perf stuff in it because it gives you control of memory layout and what gets evaluated at compile time, so it'll get you within spitting distance of an optimised c++ implementation but with 10x better iteration speed. Thoroughly recommend it to any Comp Sci / ML researchers.

Only thing I'd wish for is better control of memory layout for mutable structs, but I know that's unlikely since that's one thing that the Julia folks want to keep abstracted from the user.