It'd be pretty simple — albeit so very much a bad idea — to run the REPL from a stream which saved everything typed in the REPL to a log read in at startup. A

It'd be pretty simple — albeit so very much a bad idea — to run the REPL from a stream which saved everything typed in the REPL to a log read in at startup. A fancier version might allow log editing. A really fancy version might save everything to a log and offer commands to view expressions in the log & copy the desired ones to the startup file, or another file. Or one could just remember to move corrected source back to the right place. This is probably somewhere where a Smalltalk image-based browser would be preferable — it would/could unify the REPL and editing source.