Add Nix build configuration

[spenserblack]

This adds configuration to build the package with Nix tooling.

It also adds instructions to build from source to INSTALL.md.

See https://nix.dev/manual/nix/2.28/command-ref/new-cli/nix3-flake.html

Closes #26

[spenserblack]

@koibtw The Nix is happening

[koibtw]

WOW 😮
you should look into flakes and make a flake for this
then u can use nix eval or even nix build in CI
here https://nix.dev/concepts/flakes
simple example https://codeberg.org/koibtw/kitget/src/branch/main/flake.nix

[spenserblack]

I'm thinking I'll have both default.nix and flake.nix so that there's both the old way and the new way (flake.nix is an experimental feature IIRC?)

[koibtw]

well...... thats not really how that works. flakes are experimental but like literally 90% of nix users use flakes
flake can contain things like packages (your default.nix) and other stuff. it's just all managed in one place. you should look at my kitget example (updated it a minute ago), its fairly simple.

[spenserblack]

Alright, thanks! Will check out flakes, then.

[spenserblack]

I followed examples in Nix docs and ended up writing something pretty different from your example. It's a mix of me being a beginner to Nix tooling and wanting to keep things simple.

It works (builds to ./result), but what do you think? Am I doing anything unwise or evil?

[koibtw]

awesome!!!!!!

[koibtw]

Suggested change

	nixpkgs.url = "github:NixOS/nixpkgs";
	nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";

you should NOT be using master

[spenserblack]

Any difference between this and github:NixOS/nixpkgs?ref=nixos-unstable?

[koibtw]

nope, its the same

[spenserblack]

OK, cool. I'll just go with that since that's what nix flake init defaulted to.

[koibtw]

Suggested change

run: nix-build

nix-build -E "with import <nixpkgs> { }; callPackage ./nix/package.nix { }"

you should use it like this but you dont need it anyway since its the same package

[koibtw]

you dont need a default.nix at all

[spenserblack]

Not for flake.nix, but I think I need it so that users can build it the "old" way with nix-build instead of nix build, right? Since the docs noted some controversies with Flakes I figured I would let users also use the old way if they wanted. I guess nix-build -E "with import <nixpkgs> { }; callPackage ./nix/package.nix { }" would let me get rid of it but it's kind of nice to just call nix-build I guess 🤷

What do you think?

[koibtw]

i mean i wouldnt do that personally but if you have to, then instead of doing it that way, just put this in default.nix

with import <nixpkgs> { }; callPackage ./nix/package.nix { }

[koibtw]

one With Nix with nix build is probably fine

[spenserblack]

@koibtw Thanks for helping so much with getting Nix builds set up ❤️

[koibtw]

i mean i wouldnt do that personally but if you have to, then instead of doing it that way, just put this in default.nix

with import <nixpkgs> { }; callPackage ./nix/package.nix { }