lib.ron: init

[HeitorAugustoLN]

Adds functions for parsing and generating RON (Rusty Object Notation) data.

Basically upstreaming some functions from cosmic-manager, for use in nixpkgs (system-wide COSMIC configurations, upstream some modules to home-manager, other modules, etc.), asked by some users in HeitorAugustoLN/cosmic-manager#34.

Option types for ron will be done in a follow-up PR

Things done

• Built on platform:
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• Tested, as applicable:
  • NixOS tests in nixos/tests.
  • Package tests at passthru.tests.
  • Tests in lib/tests or pkgs/test for functions and "core" functionality.
• Ran nixpkgs-review on this PR. See nixpkgs-review usage.
• Tested basic functionality of all binary files, usually in ./result/bin/.
• Nixpkgs Release Notes
  • Package update: when the change is major or breaking.
• NixOS Release Notes
  • Module addition: when adding a new NixOS module.
  • Module update: when the change is significant.
• Fits CONTRIBUTING.md, pkgs/README.md, maintainers/README.md and other READMEs.

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[qweered]

nixpkgs-review result

Generated using nixpkgs-review-gha

Command: nixpkgs-review pr 440544
Commit: ce59159cb49ffd3a51e1322c96b0bfefbb9fa5c6 (subsequent changes)
Merge: ea27617d2c18116cc99345583a6d9fd0c3f6fa74

Logs: https://github.com/qweered/nixpkgs-review-gha/actions/runs/17668045194

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x86_64-linux

⏩ 2 packages blacklisted:

• nixos-install-tools
• tests.nixos-functions.nixos-test

✅ 1 package built:

• nixpkgs-manual

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aarch64-linux

⏩ 2 packages blacklisted:

• nixos-install-tools
• tests.nixos-functions.nixos-test

✅ 1 package built:

• nixpkgs-manual

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x86_64-darwin (sandbox = true)

✅ 1 package built:

• nixpkgs-manual

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aarch64-darwin (sandbox = true)

✅ 1 package built:

• nixpkgs-manual

[qweered]

Approved automatically following the successful run of nixpkgs-review.

[roberth]

Preliminary review. I've had a look at the overall design, but very little at the implementation.

Testing

This is a lot of intricate code, so it needs tests.
You can add them in lib/tests.
A basic test strategy would be to use lib/tests/misc.nix, but for really good coverage, you could generate pairs of RON and expected parsed Nix values with a Rust program. (rnix, or just go via JSON).

Documentation

Format lgtm overall, but the new sublibrary needs to be added in doc/doc-support/lib-function-docs.nix.
Not sure if we have something for an introductory section to lay out the in-Nix format, but I guess toRON could just refer to fromRON to achieve something similar.

[roberth]

This needs introduction, but should it even be generated by the parser?

[HeitorAugustoLN]

I improved the documentation for the raw type to cover its uses.

Regarding your question, the parser generates raw values to prevent data loss on high-precision floats and to handle unsupported syntax without crashing.

The raw type is also useful when generating RON with toRON, as it allows a user to inject a pre-formatted raw string. This offers more flexibility for complex values or for syntax the builder doesn't support (which currently doesn't happen).

Similarly to:

nixpkgs/lib/generators.nix

Lines 885 to 888 in 7e246f7

	mkLuaInline = expr: {
	_type = "lua-inline";
	inherit expr;
	};

For me, it seems like a valuable feature. I'm open to other ideas if you have a different approach in mind.

[GetPsyched]

Thanks for the effort to upstream this, @HeitorAugustoLN!

I had a small request (can be done in a followup PR): Could this new generator also be added to pkgs.formats as pkgs.formats.ron?

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Is there anything pending on this PR? I'd like to use this feature soon.

[HeitorAugustoLN]

I had a small request (can be done in a followup PR): Could this new generator also be added to pkgs.formats as pkgs.formats.ron?

It is already done in #442207

[GetPsyched]

Nice! Thanks!

[cguentherTUChemnitz]

It would be really nice, if something of the merge process would unblock this. This is the starting point of a merge-request series to bring in nixos home-manager automated theming of cattpuccin for cosmic desktop environment. I am really missing this, since every other component is properly themed already.

[caniko]

I too think it should be in nixpkgs! I made ronix without knowing this was in progress! Anyway I think ronix can still be used for mapping ron files to nix configurations, very useful for migration!