hpack all packages in a project with one invocation

[quasicomputational]

Currently, hpack is totally project-agnostic. If you're working in a project with multiple packages and you want to regenerate many or even all of the .cabal files, you have to invoke hpack for each package. For cabal-install projects, that can be quite the hardship; it's OK for stack because of the built-in hpack integration (i.e., stack build will regenerate the package descriptions for you).

I think it'd be nice to have a hpack mode that'd re-run hpack for all the packages in the project. This would need a --project-file flag to point hpack at the .project file, if it's in a non-standard place. There's also the problem that cabal.project files don't have a parser we can use. (I do have some code for this but it'd need some polishing before release.)

[sol]

How about find -name package.yaml -exec hpack {} \;?

[sol]

Not eager to add cabal specific features, but we could consider to do the find equivalent on e.g. --all.

[quasicomputational]

One problem with that is that it'd not work if you're in a subdirectory. cabal-install and stack both go up the directory tree until they find a project description and then they'll do the right thing, but presumably hpack --all wouldn't.

[sol]

@quasicomputational if a proper solution to this requires to be aware of cabal.project then do you think having this in a separate executable/project would be an option?

[JonathanILevi]

I think that the best solution would be to be cabal.project aware. Using hpack on only and all the packages in cabal.project (or more ideally some way to specify which ones). Maybe a project.yaml? Either way I think a separate executable would be fine (hproj? 😄)

[sol]

@quasicomputational did you do anything here? I would want to see a proof-of-concept of this in a separate project / executable.

[quasicomputational]

No, I never wound up writing anything to do this that would've been anywhere near suitable for general consumption - all entangled with other considerations.

[philderbeast]

I use a fairly simple shake build script for generating cabal files in a project. It uses package.dhall files instead of package.yaml. I build this project and invoke with a bash script but maybe it could be done with runhaskell?