Luckily I have a totally revamped debugging and logging system that will put us ahead of the curve here (imagine DTrace at a program level). Probably a point release of V10.
Same goes with multiple undo and retina support -- we know how embarrassing their absence is, and we've luckily been able to fix these for v10. I've been in design meetings where the multiple undo has bumped several other desirable features off our roadmap.
I'd kill for hashmaps, some sort of records and strong typing in Mathematica.
https://reference.wolfram.com/language/guide/Associations.ht...
So now there's just strong types and something like records left for me for general purpose development.
obj["a"] = 1;
obj["b"] = 2;
Print[obj["a"]]
or obj = { "a" -> 1, "b" -> 2 };
Print["a" /. obj]
?Unless it's the same kind of curve Go is judged against (aka the curve of 30 years ago), that's a very tall order. Are you working on something better than a time-traveling debugger?
> imagine DTrace at a program level
so... DTrace?
As for the REPL and general editing, if I were you, I'd quickly go towards LightTable integration — it should be doable, and the effects could be spectacular.
Still, would be interesting to try. I have great enthusiasm for what Chris Granger is doing.