Parallel graph & nested exceptions

[gfredericks]

Haallooooooo,

I've been using par-compile and every time it crashes I get my exception wrapped up nicely in 6 ExecutionExceptions hoo ray!

Should par-compile maybe use modified futures that unwrap exceptions? I'm not sure exactly how to do this, but if we can figure out a clean way is it a good idea? Should we leave one wrapper just for funsies?

[w01fe]

par-compile was really just meant as a demonstration -- it's suboptimal in a bunch of ways, not least that it creates one thread for each node, which is why you see so many levels of nesting. It might be worth looking at the experimental async compile, which does more appropriate scheduling and should be adaptable to the parallel use csae.