Show unified stack traces

[sebasguts]

Develop a way to show stack traces of both Julia and GAP function call stacks in the right order when an error occurs.

[fingolfin]

So you want to display those stack traces interleaved. From the GAP side, I can imagine a way that would allow this at least in principle (with some considerable effort); basically, we can detect where a Julia function is called, and then at these points ask Julia to fill in the missing bits of the stack trace. But for this to work, also the Julia side needs to help us out, either by being able to do the same in reverse, or at least by giving us the stack trace information in a way that is amenable to modifications before being printed.

Anyway, I agree it'd be a nice feature. But it probably should be way down on the list of things to work on; even stuff that's closely related to this. Like, it'd be nice if in a GAP using Julia GC, using ctrl-C to trigger a break loop was possible (instead of crashing GAP). And after that works, make it usable if GAP code is running that was called from Julia. I probably could go on...

Continuing this tangent, maybe starting to work on a roadmap with desirable features would be useful; this could be done as a set of issues here with suitable labels; or using https://github.com/oscar-system/GAPJulia/projects