It can already kind-of do a REPL, so it'd be about making sure access to that functionality was robust, and then it's a matter of removing packages from the system until it's as small as you'd like. Assuming a subtractive approach, of course. There are other interesting subtractive approaches like Craig Latta's "Context" (nee Spoon) http://www.netjam.org/spoon/ which does something a bit like a page cache, marking used methods, classes, etc and eventually garbage-collecting those not used. In Craig's system, there's an upstream over the network from which missing classes/methods/etc can be faulted in, so this isn't as scary as it sounds. Then there are the additive approaches, which I've kind of lost track of, but there are several on the go, for compiling a fresh image from scratch from sources.
tonyg|2 years ago