Here's a deriv example in Go: https://play.golang.org/p/kUM5qn7oiXg https://play.golang.org/p/kUM5qn7oiXg I find that it follows the functional spec quite clos

Here's a deriv example in Go: https://play.golang.org/p/kUM5qn7oiXg https://play.golang.org/p/kUM5qn7oiXg I find that it follows the functional spec quite closely, thanks to Go functions being first class citizens.