Today I've been able to do some serious REPL driven development with #spacemacs and #python and I really, really liked it. I was working on some code that was mainly implemented with a bunch of functions (although not really functional). With spacemacs you can hit <space><m><s><F> (sounds harder than it is) and the whole function is send to the Python REPL and can immediately be used. The REPL is also focused directly. This way I could re-evalute changes very fast and had an immediate reponse.
While this was working with this particular piece of code, it surely wouldn't be so nice with object oriented code, since methods are mostly not side effect free. You'd have to load whole objects into the REPL and you'd have to consider a lot more moving pieces between re-evaluation. While this would be possible, I imagine this would take the fun out of it. One more advantage of functional programming I guess.
@oldmankris with the Python layer of spacemacs you are using ipython. At least if it is installed. Otherwise it defaults to the standard python REPL. But you are right, ipython is much nice. Although this is far from what you get with Clojure, where you can start the whole project and connect to it.
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