shell completions

[KiaraGrouwstra]

it would be nice to get shell completions for npins commands.
considering a full npins update action a bit more intensive in terms of rebuilds, i've found myself manually updating pins for my dependencies. as such, i noticed shell completions were currently missing still, while these might help facilitate this process a bit.

[piegamesde]

Agreed. Clap, our CLI framework, can generate most of it, but having completions for pin names would be cool too, though that would require some extra shell magic

[Coca162]

Since we expect users of npins to be using it installed via nix, I think having the shell completions built at compile time would be the most ideal, since generating them at runtime shouldn't be necessary to anyone if they packaged in nixpkgs already. For reference here is a example I found of generating completions at compile time https://github.com/Aloso/to-html/blob/main/build.rs. We would also probably be able to append the extra logic onto the generated completitions necessary for pin names afterwards as well.

I'd wish for libnpins and the CLI parts of the codebase to be fully split into 2 crates before doing this, since without it libnpins users would be including dependencies and running a build.rs for completions they do not care about. Once the progress bar PR is done I would be happy to start working on that though.

[andir]

I don't think we need build.rs at all to generate the completion during compile time if we target the nix users (mostly). We can just run npins $whatever > $out/share/... in the build and be done.

[Coca162]

Yeah dynamically generating them and then including them in would also be possible, I also found a alternative approach to just make separate binary just for generating completions, though this approach wouldn't work well with the rust completion engine since by design that needs the completion dependencies included at runtime.