Pronoun notation

Pronoun sets: They're often notated with slashes, such as in she/her or he/they. Some time in the past I saw a meme which pointed out using exclusively slashes between pronouns has some ambiguity, and offered some symbols that could be used less ambiguously (and then humour; such is the nature of memes).
But what if this notation were to be expanded and explicitly defined somewhere? I attempted to do that for some reason.

The original meme

$multiple pronouns. she/they: ambiguous. she&they: use both, and switch it up often (bonus points for midsentence pronoun switch). she|they: choose any, they're all okay. she>they: she is best, but also cool with they. she\they: Windows file system. she☭they: our pronouns. she⊕they: I'm pretty sure these notes are for math class.$

Pronoun-set notation specification (using ABNF)

pronoun-set = precedence-set / "any" ("&"/"|") " except " exception-set

exception-set = declension-set *("," declension-set) ; one or more <declension-set>s separated by commas
precedence-set = equal-preference-set *(">" equal-preference-set) ; one or more <equal-preference-set>s separated by greater-than signs
equal-preference-set = mix-set *("|" mix-set) / OPWS "any|" OPWS ; one or more <mix-set>s separated by vertical bars, or "any|"
mix-set = declension-set *("&" declension-set) / OPWS "any&" OPWS ; one or more <declension-set>s separated by ampersands, or "any&"
declension-set = pronoun *("/" pronoun) ; one or more <pronoun>s separated by slashes
pronoun = OPWS (1*ALPHA / "ask pronoun") OPWS ; <pronoun> is one or more letters, or the string "ask pronoun"
OPWS = [WSP] ; optional whitespace

ALPHA here is not necessarily ALPHA from the ABNF core rules; here I am using ALPHA to mean letters in general. I will not attempt to specify what "letters in general" means here because there are a lot of writing systems.
For backwards-compatibility purposes, if a pronoun set's only non-letter characters are the slash and optionally whitespace, it may be interpreted as multiple declension sets separated by slashes.

Why did I use ABNF? There are an overwhelmingly large number of metasyntax notations; it is hard to choose one. In the end I chose ABNF because ABNF has a public specification.

Some example use cases

she&they, she|they, she>they from the meme
she/they is allowed too; here the reader needs to use context to determine this is multiple declension sets separated by slashes
any&: any pronouns, switch it up often
any|: any pronouns, switching it up often is not required
any& | xe/xir: switch up any pronouns, or use xe/xir (this is an instance in which optional whitespace is useful because otherwise this'd end up containing the string &|)
any| except he,she: any pronouns, except for he and she. Switching it up often is not required.
ask pronoun>she: asking for pronoun is best, but also cool with she. (good for if you are not always able to reply to requests for pronouns in a timely manner)
ask pronoun/em/eir/eirs/ask pronoun > e/emself: ask only for certain declensions (with unable-to-reply-to-requests-in-a-timely-manner in this case being Spivak). (also observe that declensions don't have a set order, though nominative/accusative/possessive determiner/possessive/reflexive seems to be common in English)
they&he|they&she: either switch between they and he or switch between they and she
they>he|she: they is best, but he or she are equally okay as well

Are there use cases which this spec doesn't cover? Quite possibly! In that case this spec could be superseded by another spec. In that case I would request that you follow the Design goals below, but I can't force you or anything

Design goals

My design goals for this spec were:

Be able to represent many pronoun sets
Be backwards-compatible (with existing slash notation and the meme's first three items I guess)
Be somewhat human-readable

neat now this thing is on the world wide web

hope this has been enjoyable to read i guess