As a data format, yaml is extremely complicated and it has many footguns. In this post I explain some of those pitfalls by means of an example, and I suggest a few simpler and safer yaml alternatives.

A 10 minute read covering some YAML edge-cases that you should have in mind when writing complex YAML files

  • FizzyOrange@programming.dev
    6·
    9 months ago

    The problem is there aren’t really any good alternatives that have as widespread support. I’ve looked at lots and always found some annoying flaw that JSON or YAML don’t have. I mainly want good support in Python, Rust and VSCode.

    • JSON5: This is my ideal alternative but it has surprisingly poor support. No good VSCode extension. There’s a Serde crate but it’s not very popular.
    • Jsonnet: This has great VSCode support and support for lots of languages including Rust, but for some inexplicable reason they won’t let you use it with Serde just to load documents.
    • TOML: This is just not a good format. It’s ok for very basic things but any level of nesting and it becomes even worse than YAML.
    • Cue: Only supported language is Go.

    There isn’t really a perfect option at the moment IMO.

    If I’m using Rust I tend to go with RON at the moment. Sometimes I do use YAML but I write it as JSON (since YAML is a superset of JSON) with # comments.

    Also never output YAML from your programs. You can always output JSON instead which is better.

    • Rose@lemmy.world
      3·
      9 months ago

      My hierarchy goes something like this:

      • A relatively trivial configuration file? TOML
      • A configuration file that needs a bit of complexity and nesting? YAML
      • Is it getting so complicated and longwinded that you’re actually unlikely to touch it by hand anyway? JSON
      • Have we become downright enterprisey? XML