It makes me a bit worried to read this thread, I would've thought its pretty common knowledge why CSV is horrible and widely agreed upon. I also have hard time taking anybody seriously who uses "specification" and "CSV" in the same sentence unironically.

I suspect its 1) people who worked with legacy systems AND LIKED IT, or 2) people who never worked with legacy systems before and need to rediscover painful old lessons for themselves.

It feels like trying to convince someone, why its a bad idea to store the year as a CHAR(2) in 1999, unsuccessfully.

Just don't write that love letter in French ... or any language that uses comma for decimals

Actually even whitespace-separated json would be a valid format and if you forbid json documents to be a single integer or float then even just concatenating json gives a valid format as JSON is a prefix free language.

That is[0] if a string s is a valid JSON then there is no substring s[0..i] for i < n that is a valid json.

So you could just consume as many bytes you need to produce a json and then start a new one when that one is complete. To handle malformed data you just need to throw out the partial data on syntax error and start from the following byte (and likely throw away data a few more times if the error was in the middle of a document)

That is [][]""[][]""[] is unambiguos to parse[1]

[0] again assuming that we restrict ourselves to string, null, boolean, array and objects at the root

[1] still this is not a good format as a single missing " can destroy the entire document.

The byte for a capital I is the same as the start for an odd file format, slyk maybe? Excel has (or did if they finally fixed it) for years decided this was enough to assume the file (called .csv) cannot possibly be csv but must actually be slyk. It then parses it as such, and is shocked to find your slyk file is totally broken!