What would be a good programming language to speed up Elixir?

Oh Rustler looks awesome, thanks for mentioning it ^-^

What do you mean, seed up? Speed up? If so in what context?

In a general context, may be for some number crunching

In general context it is regarded more than fine. By number crunching, what specifically?

I would imagine the instances of needing to create a nif to call would be small and/or specialized. Maybe the question should be “What other languages can I use to create a NIF to call from Elixir/Erlang?”

well that’s the idea

For number crunching purposes, I’ve had good success with writing Python scripts (i.e. numpy/scipy) that interface with an Elixir port via erlastic (the package isn’t maintained anymore but works for the most part – look at the forks too). It’s way less of a hassle than writing NIFs in my opinion, although obviously somewhat less sexy

There is also erlport which lets you invoke python functions directly from erlang/elixir - this branch seems to be the most active: https://github.com/beano/erlport

In general ports are preferred over NIFs because they can’t mess-up the run-time environment.

For OP: in general people do not recommend languages for interop that have their own the garbage collector and run-time environment. It might be possible but you will not be doing yourself any favors. This really does make your practical choices C, C++ or Rust.

Like I mentioned though - interop can also be done via term exchange either over a network or through the port interface. Haskell has a pretty recent library that does term encoding and network communication. Honestly I’d prefer to use something in a port interface - thats a lot less to mess up on the foreign library’s side. I think Haskell could be used in the port interface with just the term conversion from hinterface.

I also found this for OCaml; it has more support for the port interface.

Good libraries, I think the best and safe option could be rust