It depends on how they parse/decode/unmarshal the file. If they use a "generic" yaml parser, no will be translated to false. But if the parser knows the types of the data structure, or can be instructed not to replace certain strings, or has hooks, it can treat no as a string. So it might be that the linter doesn't operate like the parser.

[delayed]

> Almost all of this is solved by basically putting quotes around strings.

Yeah, that was my first thought as well. I personally don't mind YAML, but I've also made a habit out of quoting strings. And, I mean, you're quoting both keys and strings in JSON, so you're still saving approx. 2 double quotes per key/value pair in YAML if that's a metric that's important to you.

JSON doesn’t do them as part of the spec, but there’s nothing stopping you from doing them as post-processing. Eg OpenAPI does it by using a special $ref key where the post processor swaps in the value referenced there.

That’s effectively what jsonnet/cue/hcl do, though as a preprocessor instead of a postprocessor.

This is basically every problem in YAML. Someone couldn't resist adding more stuff and either didn't realise or didn't care about the ambiguities it created.

I wish I had a good answer for you. I've been dissatisfied with Dhall, Nickle, Cue, and possibly others. Dhall's type system is both too strong (you have to plumb type variables by hand if you want to do any kind of routine FP idioms) and too weak (you can't really _do_ much with record types - it's really hard to swizzle and rearrange deeply nested records).

On top of that, the grammar is quite difficult to parse. You need a parser that can keep several candidate parses running in parallel (like the classic `Parser a = Parser (String -> [(a, String)])` type) to disambiguate some of the gnarlier constructs (maybe around file paths, URLs, and record accesses? I forget). The problem with this is that it makes the parse errors downright inscrutable, because it's hard to know when the parse you actually intended was rejected by the parser when the only error you get was "Unexpected ','".

Oh, and you can't multiply integers together, only naturals.

Maybe Nix in pure eval mode, absurd as that sounds?

I think the best thing for tools to do is to take and return JSON (possible exception: tools whose format is simple enough for old-school UNIX-style stdin/stdout file formats). Someone will come up with a good functional abstraction over JSON eventually, and until then you can make do with Dhall, YAML, or whatever else.