This made me realize that some emojis are poorly named,

It's a lot of them. My recentish pr only covered a small part.

I'll be the first to bring up automation here:
Whether we want to automate this in the future or not, I think we should definitely have all of these hard-coded in the source code, since such automation would probably take a lot of time that we shouldn't have to pay on each build.
The automation would then only be an optional verification step like in #9. (And maybe we always enable it in CI)

That means any concerns about such automation should not block this PR.

I had to find a way to be confident in the content of this PR anyway, so I figured I could make tests so that the automation part is already done. I left a commit with the tests failing, so that you can see the output in CI. Notably, there was one mistake introduced in ae98eb0: I added the text presentation selector to sym.dash.wave instead of sym.dash.wave.double.

For now, I query the list of presentation sequences defined by Unicode from the internet every time the tests are run. Feel free to suggest a better way.

This PR now contains meta changes.

For now, I query the list of presentation sequences defined by Unicode from the internet every time the tests are run. Feel free to suggest a better way.

How about caching it in a file cache/presentation-sequences.txt and adding /cache/presentation-sequences.txt to the .gitignore?

Also, I'd like the web-request part of this test to be opt-in to begin with (the test can still run without it if the cache file already exists). IMO running cargo test shouldn't perform any web requests without the user's consent. A crate feature for this would also have the advantage of making the reqwest dependency optional.

Initially I thought it may be better to download the file as part of a build script for tests only (which would cache it for as long as the source code is not modified), but I'm not sure how to run something only for building tests? Also, maybe this is a bad idea for some other reason. I think your solution is probably better anyway. Maybe the file could even be part of the repo so that it doesn't need to be downloaded every time, but somehow that doesn't feel right to me. Also, that might have some licensing issues (we would probably need to include https://www.unicode.org/license.txt as well).

Additionally, I want to clarify that the dependency on reqwest is for tests only.

Additionally, I want to clarify that the dependency on reqwest is for tests only.

Yeah I got that, but it's still a huge dep tree that not everyone may want to have to download before running [the rest of] the tests.

If we're gonna go with the downloading thing, then ureq would already be a lot smaller than reqwest.

I switched to ureq. Additionally, the file is now pinned to Unicode 16.0.0 so as to prevent sudden breakage when a new Unicode version releases. The file is now downloaded in build.rs. To prevent always having ureq as a build dependency, I hid the tests that require it behind a non-default _test-unicode-conformance feature and added it to CI.

According to The Cargo Book, it is not possible to have a build dependency for tests only, so this feature trick is necessary:

The same applies to cfg(debug_assertions), cfg(test) and cfg(proc_macro). [...] There is currently no way to add dependencies based on these configuration values.

Would it be possible to have some shorthand that specifies text vs emoji form? \u{FE0E} isn't particularly readable

Could be \vs1–\vs16, or alternatively \evs and \tvs for "emoji variation selector" and "text variation selector" only.¹

Or \emoji and \text

An alternative is to simply paste the corresponding codepoints in the symbol lists

An alternative is to simply paste the corresponding codepoints in the symbol lists

That defeats the point of having escape sequences to begin with. We could also paste in the zwj and friends verbatim, but that's terrible for editing, diffing, etc.

Or \emoji and \text

This (only with ! instead of \) was also what I originally suggested in #92. Using a backslash is way better tho, so I actually like this more than my original idea.

Or \emoji and \text

I think this would be good

The other variation selectors have multiple roles, and therefore aren't easy to name. Maybe \vs1, \vs2, ... \vs15 and \vs16 with \text and \emoji possibly being alternative names for the final two? Even just \vs1 - \vs16 would be more readable than \u{fe00} - u{fe0f}

There's a couple dozen mathematical symbol variants involving VS1

https://www.unicode.org/Public/16.0.0/ucd/StandardizedVariants.txt

Edit: Only selectors 1-4, 7, 15 and 16 are currently in use.

I implemented \vs{1}--\vs{15}, as well as \vs{text} and \vs{emoji}.

I think all the concerns were addressed and so this is ready for review