haskell.nix integration

[walkah]

Another VERY WIP EXPERIMENT using haskell.nix to build proper nix packages for fission cli + server.

Known issues:

• [ ] Builds a lot of stuff (there is no binary cache for aarch64-darwin at all, and minimal stuff on x86_64 platforms)
• [x] current stack-based build / install workflow doesn't work (only nix build)

[tennox]

I forgot to check first if an existing PR is doing what I was doing, so I duplicated this: #623 :see_no_evil:

But then, checking your checklist of known issues, I think I managed to not break the existing workflow - stack build still works fine in the devshell.

I also managed to use the binary cache (linux x86_64), at least for the basics (like ghc) - the haskell packages themselves still took quite some time to build. But this is the same with stack build (for me)?

Maybe you check it out yourself? As I never actually used a stack-based haskell workflow and I'm not too sure about it.

[walkah]

I also managed to use the binary cache (linux x86_64), at least for the basics (like ghc) - the haskell packages themselves still took quite some time to build. But this is the same with stack build (for me)?

totally right! I was tinkering with two approaches in parallel ... I've rebased against the dev setup in main and it looks like it's all working pretty well. thanks for poking around! 🙏