Yes, there are tools like rcrl (mentioned in the blog post) that dynamically link in new pieces of code [1]. The author of rcrl gave a nice talk at CppCon [2].

The trouble with tools like that is that they're pretty language specific, so it's my impression that it would require a fair bit of work to generalize to languages other than C++.

[1] https://github.com/onqtam/rcrl

[2] https://www.youtube.com/watch?v=UEuA0yuw_O0