I'll use a Guile or SBCL REPL for some quick math (assuming it's something that's not trivial in dc) or to test out a quick idea, but I rarely send more than one to three forms before closing it. That's only if I don't have Emacs open where I can just do it in the scratch buffer. Anything that needs more than a couple defuns goes into SLIME or guiser.
So, people who use native REPLs, what do you do with them?
In my case, I use my interactive shell https://github.com/cosmos72/schemesh every day as login shell.
You can look at it as heavily customized Scheme REPL, where everything not inside parentheses is parsed and executed as shell syntax, and everything inside parentheses is parsed and executed as Scheme syntax.
Having arithmetic and procedure definition within the login shell definitely feels liberating, at least to me
Anyway, a few years ago dang changed the backend to SBCL that is more REPL friendly, so I guess this comment is showed using the REPL of Arc in the REPL of SBCL.
But maybe I am strange, because I got to experience Smalltalk transcript, Oberon REPL, AmigaDOS and REXX, was into XEmacs when there were no UNIX based IDEs to chose from, got to use VB REPL before Microsoft killed it on VB.NET, Alegro Common Lisp, Caml Light,...
And I guess that is why nowadays I am a big Powershell fan, even if it errs on the verbosity side.
It is like having the debugger always turned on, and being able to script the OS as well.
I think I'll give your workflow a try. I might learn something interesting from it. Worst case, I'll gain new appreciation for SLIME.
(I like your books, BTW.)
Instead he interacts with it via his editor's tooling, where you are in a normal file, and use a shortcut that will send a sexp/function/region/etc into the running repl and display the result.
So just to be clear you are using the repl directly?