A simple language made from this tutorial: https://llvm.org/docs/tutorial/MyFirstLanguageFrontend/index.html

docker build -t docker-kaleidoscope .
docker run --rm -v /home/sparkle/kaleidoscope/example:/example docker-kaleidoscope /example/fib.ka

It will make the example/fib.o file.

Suppose you have this code in fib.ka:

# Compute the x'th fibonacci number.
def fib(x)
  if x < 3 then
    1
  else
    fib(x-1)+fib(x-2)

And this code in main.cpp:

#include <iostream>

extern "C" double fib(double);

int main() {
    int n;
    while (std::cin >> n) {
        std::cout << fib(n) << std::endl;
    }
}

After compiling fib.ka to fib.o, you can link this file with C++ code:

clang++ main.cpp fib.o