rust-cssparser VS bstr

If you were to implement this yourself, i'd look into either swash or cosmic-text for the text rendering stack (this is one of the things you really don't want to write from the ground up). For accessibility, AccessKit has quickly become the standard for communicating with crossplatform accessibility APIs in rust GUI. lightningcss (or its lower level counterpart cssparser) are both decent options for CSS parsing. Taffy handles some of what browsers offer for a layout engine, but is still being worked on.

Libraries for a lot of this stuff exist (albeit in many cases not very mature yet):

- https://github.com/pop-os/cosmic-text does text layout (which Taffy explicitly considers out of scope)

- https://github.com/AccessKit/accesskit does accessibility

- https://github.com/servo/rust-cssparser does value-agnostic CSS parsing (it will parse the general syntax but leaves value parsing up to the user, meaning you can easily add support for whatever properties you what). Libraries like https://github.com/parcel-bundler/lightningcss implement parsing for the standard css properties.

- There are crates like https://github.com/BurntSushi/bstr and https://docs.rs/wtf8/latest/wtf8/ for working with non-unicode text

We are planning to add a C API to Taffy, but tbh I feel like C is not very good for this kind of modularised approach. You really want to be able to expose complex APIs with enforced type safety and this isn't possible with C.

Libraries for a lot of this stuff exist (albeit in many cases not very mature yet):

- https://github.com/pop-os/cosmic-text does text layout (which Taffy explicitly considers out of scope)

- https://github.com/AccessKit/accesskit does accessibility

- https://github.com/servo/rust-cssparser does value-agnostic CSS parsing (it will parse the general syntax but leaves value parsing up to the user, meaning you can easily add support for whatever properties you what). Libraries like https://github.com/parcel-bundler/lightningcss implement parsing for the standard css properties.

- There are crates like https://github.com/BurntSushi/bstr and https://docs.rs/wtf8/latest/wtf8/ for working with non-unicode text

We are planning to add a C API to Taffy, but tbh I feel like C is not very good for this kind of modularised approach. You really want to be able to expose complex APIs with enforced type safety and this isn't possible with C.

As the author of bstr and also the regex implementation that bstr uses to implement word breaking, it is linear time.

NSFL: https://github.com/BurntSushi/bstr/blob/86947727666d7b21c97e...

OsStr uses WTF-8 on Windows, and just represents the raw underlying bytes on Unix.

Byte strings can be WTF-8. They can be anything. The problem is that there is no real way to (easily) get the underlying WTF-8 bytes of an OsStr on Windows. So there's no free conversion to and from byte strings.

I wrote more about this in the bstr docs (and don't miss the link to os_str_bytes): https://docs.rs/bstr/latest/bstr/#file-paths-and-os-strings

I'd be happy to answer more questions if you have them. :-) https://github.com/BurntSushi/bstr/discussions

Check out bstr, which does this exact thing for its BString and BStr types.

Currently slated for next Monday: https://github.com/BurntSushi/bstr/issues/40

This is just an FYI. I don't mean to say much to your overall point, although, as someone else who has spent a lot of time doing Unicode-y things, I do tend to agree with you. I had a very similar discussion a bit ago.[1]

Putting that aside, at least with respect to grapheme segmentation, it might be a little simpler than you think. But maybe only a little. The unicode-segmentation crate also does word segmentation, which is quite a bit more complicated than grapheme segmentation. For example, you can write a regex to parse graphemes without too much fuss[2]. (Compare that with the word segmentation regex, much to my chagrin.[3]) Once you build the regex, actually using it is basically as simple as running the regex.[4]

Sadly, not all regex engines will be able to parse that regex due to its use of somewhat obscure Unicode properties. But the Rust regex crate can. :-)

And of course, this somewhat shifts code size to heap size. So there's that too. But bottom line is, if you have a nice regex engine available to you, you can whip up a grapheme segmenter pretty quickly. And some regex engines even have grapheme segmentation built in via \X.

[1]: https://github.com/BurntSushi/aho-corasick/issues/72

[2]: https://github.com/BurntSushi/bstr/blob/e38e7a7ca986f9499b30...

[3]: https://github.com/BurntSushi/bstr/blob/e38e7a7ca986f9499b30...

[4]: https://github.com/BurntSushi/bstr/blob/e38e7a7ca986f9499b30...

This is a great idea. I realize the find implementation is not ideal and have considered bringing in an optional dependency to improve performance. I remembered bstr using two-way search, so I was wondering if depending on the full crate for searching would be worthwhile, but I see that changed. Thanks for the tip!

Fun little nit-pick that does not detract from your overall point: you can actually count graphemes with a regex and that's exactly what bstr does. :-)