rust-cssparser

I haven't really looked at the fastrender project to say how much of a browser it implements itself, but it does depend on at least one servo crate: cssparser (https://github.com/servo/rust-cssparser). Maybe there is a main servo crate as well out there, and fastrender doesn't depend on that crate, but at least in my mind fastrender depends on some servo browser functionality. EDIT: fastrender also includes the servo HTML parser: html5ever (https://github.com/servo/html5ever).

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

We actually already have! I contributed hwb() color support as part of my work on Parcel CSS, and it shipped in Firefox 96! https://github.com/servo/rust-cssparser/commit/62d63fea751df...

> Parcel CSS is based on the cssparser[0] Rust crate, a browser-grade CSS tokenizer created by Mozilla and used in Firefox. This provides a solid foundation, including tokenization and basic parsing. However, it does not interpret any CSS properties or at rules. That's where Parcel CSS comes in. It handles parsing each individual rule and property value, as well as minification, compilation, and printing back to CSS. https://github.com/servo/rust-cssparser

In general, unicode requires you think differently about strings depending on context. Here's my rule of thumb. 1. If you are transporting a unicode string, reading/writing over the network or to a file, think in terms of UTF-8 bytes. Do not attempt to splice the string, treat it as an atomic unit. 2. If you are parsing a string, think in terms of code points (runes in Go, chars in Rust). A good example would be the Servo CSS parser. [1] 3. If you're comparing/searching/inspecting/sorting a string in code, segment by grapheme clusters and normalize, then do what you came to do. [2] 4. If you're displaying a string, think in terms of pixels. Do not attempt to limit a string by length in "characters" (nee grapheme clusters in the unicode world) but rather measure by what the renderer does with the string. Each character can be a thoroughly

Where did the 10% number come from? FWIW, I just looked at the code in the mozilla/servo repository: more than half (1291) of all mentions of 'unsafe' (2150) are inside autogenerated bindings to CEF (Chromium Embedding Framework), which doesn't seem at all like the interesting/relevant part of the application (it's providing an optional "minimal working" browser chrome for the rendering engine). A lot of the other uses are similarly for other FFI tasks, interfacing with libraries like FreeType, HarfBuzz and Spidermonkey. Obviously it would be nice for those libraries to be in Rust and thus avoid the FFI-is-always-unsafe , but the ecosystem is still young and those libraries are seriously non-trivial, Mozilla and the Servo team presumably want to be able to do the interesting parts of their experimentation rather than spending years portin