Special Environmental Variables

[uncomfyhalomacro]

This is a follow up for #7105. As mentioned on that issue, this is most inspired from kakoune's way of using shell-expansions.

For me it is a good feature. However, I am not sure what special environmental variables should be necessary to have if we go for this feature. My use case for this is to configure LSPs that have weird configurations e.g. Julia.

The question is, do any of you even want this?

[guissalustiano]

Yes, I discovered this on Zed (zed-industries/zed#8675) and it is pretty useful to run test in the current cursor in Elixir with

iex -S" mix test -b $ZED_FILE:$ZED_ROW

I would like to use this on helix too

[kirawi]

See #6979