Or Forth. But all of these are extreme spaghetti-bait too. Being able to see all the code that goes into an executable, and generate a clean one using only that code, is important for good development hygiene, which of course they didn't know yet in the 1970s. Imagine trying to use version control on a REPL - it doesn't work - you have to version control the commands that go into the REPL and running them on a fresh REPL every time.