I think adding progress reporting to VS Code would be feasible at this point, I’m pretty sure there are enough UI hooks to do that.
Inline results can’t be done today. The VS Code team had been working on something where one could show custom stuff between code lines, but I’m not sure whether that is going to ship anytime soon.
We will be getting a workspace view in the VS Code extension soon ™, and it will have tree drill down into composite types. It won’t use TreeViews.jl, but just be based on standard Julia type logic (i.e. you’ll be able to drill down into composite types, arrays and dicts).
But before we ship that, we’re going to ship a debugger in VS Code (which, btw. also has tree drill down during debugging).
I’m probably most excited about the notebook UI that is coming to VS Code. The core VS Code team is adding UI for notebooks, and then extensions can provide their own implementations for different backends. I’m pretty sure someone will build a Jupyter notebook extension. I plan to add support for “Julia Notebooks” that will mimic R Notebooks from RStudio (in particular in terms of file format).