JSON as currently spec'd is honestly quite bad at both jobs, but the most rational defense of its use as a data format is that it's (mostly) human readable. Given that that's its main value proposition, what exactly is the reason for saying that JSON-as-data-format should not have comments? What do we lose if we allow them?
Because JSON originally did have comments, and people were putting pragmas into them, and so different parsers would act different depending on whether they understood them or not. Comments ended up being an anti-feature in JSON because people were abusing them.
Source:
> I removed comments from JSON because I saw people were using them to hold parsing directives, a practice which would have destroyed interoperability. I know that the lack of comments makes some people sad, but it shouldn't. […]
* https://web.archive.org/web/20190112173904/https://plus.goog...
> Suppose you are using JSON to keep configuration files, which you would like to annotate. Go ahead and insert all the comments you like. Then pipe it through JSMin before handing it to your JSON parser.
Doesn't seems he is that against the idea
I would call out portability instead, which is not dependent on the byte ordering or endianness issues of binary data formats.
sort of like: javascript is portable code, json is portable data.
But there are dangers there - look at how horribly comments get abused in code:
* doctests are nonsense, just write tests. (doctests like rusts that just validate example snippets are the closest thing to good I've seen so far, but still make me nervous).
* load bearing comments that code mangling/generation tools rely on (see a whole bunch of generated scripts in your linux systen - DO NOT EDIT BELOW THIS LINE)
* things like modelines in editors that affect how programs interact with the code
* things like html or xml comments that on parsing affect end user program logic.
Comments can be abused, and in something like JSON on the wire I can see systems which take additional info from the comments as part of the primary data input. Often a completely different format... and you end up with something like the front-matter on your markdown files as found in static site generators.
Point being, comments are not a purely benign addition.
these are mostly a warning sign for humans, to be read as "if you need to modify the script below this line, a) you gotta be knowing what you're doing, we are not held liable for support if you change stuff around there b) please contact us to make sure we didn't miss a legitimate need or c) you're trying to do something in a bad way and there's better ways to do so".
I don't see anything intrinsically wrong with doctests. I also can't see a better way to do "load bearing comments," and I'm not eager to go back to "Step 2: Edit your .bashrc to include foo."
Why are doctests not tests?
> doctests like rusts that just validate example snippets are the closest thing to good I've seen so far
Rust's doctests don't seem to be fundamentally different from Python doctests, which is the language I've seen most commonly make use of doctests.