Reading and writing JSON / YAML / TOML using pkgs.formats

[jtojnar]

Nothing builtin yet. See

Is there a way to read a yaml file and get back a set?

This comes up a lot. For example, consider alacritty’s colorscheme configuration. It has a colors entry that matches the yaml config 1:1. It would be nice if we can have config.colors = fromYaml ./colors.yaml inside alacritty.nix. Currently I have to copy the yaml file, then manually change it to nix syntax when I want to experiment with stuff like this.

and

How to convert Yaml -> Nix object?

I’m trying to configure program.alacritty in home-manager where program.alacritty.settings takes in an object. I looked around and there is only builtins.fromJSON. Is there any support for YAML? I also tried creating a config file “repository” derivation where I put alacritty.yaml through yq to produce alacritty.json. However, it seems pure builds doesn’t allow builtins.fromJSON "${my-derivation}/alacritty/alacritty.json" because it targets absolute path /nix/store/... Right now, I see some d…