I would argue something else: the repl invites you to write functions that take all their state as input, due to that making repl working easier. That means fig

I would argue something else: the repl invites you to write functions that take all their state as input, due to that making repl working easier. That means figuring the code out can be the same as writing it. Now, sure, you can write a mutating statefull mess using the repl as well, but most code I have come across in CL is not like that, except for maybe the odd times you find java-in-cl. It is not the same thing, of course, but it is tangential. Pure functions is something you can write in any language, but languages where you so easily can develop/try smaller chunks make it a particularly good idea. Trying a piece of Java code usually means running a lot more code that sets up your state for you. How I, and most people I know, use a lisp repl does not.