Syntax for documenting JSON structure

Question

So I'm trying to document the format of the json returned by an api I am writing against and I'd like to know if there is any popular format for the documentation of json structure.

Note I'm not trying to to test or validate anything, I'm just using this for documentation. Also some ways to add comments to non-constants(items always returned w/ the same value) would be nice.

This the not totally thought out scheme I'm currently using:

Plain names refer to identifiers or types.
Some types have type-comment
Strings that appear to be constant(always returned for that type of request) strings are "str"
Constant Numbers would be just the number
Constant null is null
Booleans are true/false for constant booleans or Boolean otherwise
[a,b,c] are lists with 3 items a,b,c
[...  ...] is a list of repeating elements of some types/constants/patterns
{a:A,b:B,c:c} and {... ...}  is the same for a dictionary.

example:

story          := [header,footer]
header         := {"data":realHeader,"kind":"Listing"}
realHeader     := {"after": null, "before": null, "children": [{"data": realRealHeader, "kind": "t3"}], "modhash": ""}
footer         := {"data":AlmostComments,"kind":"Listing"}
AlmostComments := {"data": {"after": null, "before": null, "children": comments, "modhash": ""}, "kind": "t1"}
comments       := [...{"data":comment, "kind":"t1"}...]

realRealHeader :=
{"author": string,
"clicked": boolean,
"created": int,
"created_utc": int,
"domain": "code.reddit.com",
"downs": int,
"hidden": boolean,
"id": string-id,
"is_self": boolean,
"levenshtein": null,
"likes": null,
"media": null,
"media_embed": { },
"name": string-id,
"num_comments": int,
"over_18": false,
"permalink": string-urlLinkToStoryStartingFrom/r,
"saved": false,
"score": int,
"selftext": string,
"selftext_html": string-html,
"subreddit": string-subredditname,
"subreddit_id": string-id,
"thumbnail": "",
"title": string,
"ups": int,
"url": "http://code.reddit.com/"
}


comments := {
"author": string,
"body": string-body_html-wout-html,
"body_html": string-html-formated,
"created": int,
"created_utc": int,
"downs": int,
"id": string-id,
"levenshtein": null,
"likes": null,
"link_id": string-id,
"name": string-id",
"parent_id": string-id,
"replies": AlmostComments or null,
"subreddit": string-subredditname,
"subreddit_id": string-id,
"ups": int
}