> However, in my experience on live reloading (with QML, Unity3D and Python), it only works well with environments that don't interface to native code. Else it'

> However, in my experience on live reloading (with QML, Unity3D and Python), it only works well with environments that don't interface to native code. Else it's way too easy to leave some state hanging in a bad way in a DLL (and then you get undebuggable crashes upon undebuggable crashes). Live introspection/DOM mutation has been a life saver. For example, there was a strange change to the Gnu/Linux font stack that ended with fonts on Ubuntu 16.04 that measured significantly wider than on Windows, OSX, or even older Gnu/Linux distros. Seeing the computed value of the font in devtools gave us our first sanity check that indeed we were looking at the same font on all systems. Measuring the font by injecting a quick script into devtools showed the relevant symptom of the font stack discrepancy that we could then check for and workaround. (It also served as a check that the computed value above was indeed the correct one.) Interpreted frontend language meant pulling the code change and simply running again from the dev environment. (Admittedly a small benefit over recompiling, but a benefit nonetheless.) There's actually a decent counterexample of a similar set of problems in a separate branch of the software that uses the old Tk canvas interface. Since it has no (easy) introspection tools to gauge what's going on with the fonts, there was instead a 100+ message thread of people comparing screenshots and staring at zoomed-in pixel differences. > Likewise, there is no REPL provided (since it's declarative in nature... there are no "instructions" being executed directly, only reactions to actions). But implementing your own takes a few lines. I wonder what its point would be though. For one thing, it means not having to guess or predict which state might be relevant to a bug report. I can give a user a script to inject and then get back what the result is on their system. I've probably solved a handful of bugs this way, so it's definitely useful.