- Visualizer:
- Code:
- TOML spec:
TOML and YAML both have the problem that if you receive an incomplete document, there’s a decent chance you can’t tell. JSON doesn’t have that because of the closing curly.
Doesn’t YAML have a (seldom used) feature of a start and end of document marker? The “YAML frontmatter” that a few markdown documents have, uses this.
On the other hand, I hate that with JSON you can only store one document per file.
Some programs allow you to omit the outside braces, others require it.
But I do hate toml, and I don’t much like yaml either (why are there like 8 whitespace permutations?!)
What’s wrong with TOML? I personally think it’s great for configuration purposes.
One thing you can run into is that nesting things is hard in TOML: https://stackoverflow.com/questions/48998034/does-toml-support-nested-arrays-of-objects-tables
The syntax is simply not built for that, because
.iniformat.
Good point, I’d been interested in using toml
Every time I have reached for TOML I have ended up using JSON. The first reason is that Python standard library can read but not write TOML, which is generally useless for me. The second reason is TOML does not add any benefit over JSON. It’s not that much easier to read and IMO JSON is easier to write by hand because the syntax rules are completely obvious.
TOML is mainly for humans to write, certainly not a good choice if you’re programmatically writing files - comments and formatting would be lost.
It all depends on the library you use. Rust has you covered with toml_edit. It is what is used for all the cargo commands editing the Cargo.toml file.
Agreed. Except that it’s not easier to write imo
Where do you put your comments in JSON files?
That doesn’t really work when you need two comments at the same level, since they’d both have the same key
write json with comments. Use a yaml parser.
If you’re reaching for yaml, why not use toml?
It still works since multiple identical keys are still valid json. Although that in itself isn’t fantastic imo.
For settings files I always have an example file with sensible values filled in and along with descriptive keys that serves as reasonable documentation. If something is truly unknowable, I’ve probably done something wrong.
How would you mark a flag in your json settings file as deprecated?
In my opinion, the settings file isn’t where this information should be presented. I would put these notes in the release log and readme and example settings file. I have also written this information to logging during startup so a user knows what to do, or I write a migration that does the change automatically if that’s possible.
This is only my opinion and you can use the comment method described like
“//“: “Deprecated”if desired.
The very first moment that I had to use JSON as a configuration format, and I was desperate to find a way to make a long string into a JSON field. JSON is great for many things, but it’s not good at all for a configuration format where you need users to make it pretty, and need features like comments or multi-line strings (because you don’t want to fix a merge conflict in a 400 character-wide line).
I really don’t understand why people still insist on prohibiting trailing commas anywhere. The syntax is interesting but it looks like defining an array of objects would be needlessly difficult. I think the double square bracket syntax is far too easy to confuse.
but… trailing commas are ok in TOML
- edit 1: I now see the caveat of an inline table - though trailing commas are not that useful for an inline list of values anyways
- edit 2: they’re changing this for TOML 1.1: https://github.com/toml-lang/toml/issues/516 .
The double square bracket is for an array of tables. A regular array looks “normal”: https://toml.io/en/v1.0.0#array
The code link is cut off for me
I’ll never understand why we don’t just use s-expressions.
Why would one pick toml over yaml?
Perhaps they’re Norwegian.
Significant whitespace is the devil’s play thing.
XML < YAML < TOML < possibly others
