> outrageously bad programming languages that allow run-time code rewriting
Almost all languages allow run-time code rewriting. Some of them just make it easier than others, and some of them make it a very useful feature. If you're very careful, updating a bash script while you're running it can be useful, but most often it's a mistake; in Erlang, hot loading is usually intentional and often useful. Most other languages don't make it easy, so you'll probably only do it if it's useful.
Almost all languages allow run-time code rewriting. Some of them just make it easier than others, and some of them make it a very useful feature. If you're very careful, updating a bash script while you're running it can be useful, but most often it's a mistake; in Erlang, hot loading is usually intentional and often useful. Most other languages don't make it easy, so you'll probably only do it if it's useful.