Thank you for working on this! I agree with you that there is room for improvement on rustdoc. I'm not convinced this exact design nails it though.
Things I like:
- a search bar always visible. Even though with rustdoc it's only an "s" hotkey away, I have a hard time adapting to it and often have the reflex of scrolling. However I think it should be an instant "as you type" filter on the outline.
- I do prefer an outline on the left above the sections "Modules", "Macros", "Structs", "Traits", etc of rustdoc, which don't have much informational value. However I think there is a problem in practice. Many rust libraries are organized in modules for the developer convenience, but those modules are private, and items are re-exported. That somewhat beats the point of an outline if it becomes a mostly flat list under "prelude". That being said maybe we need to see it on some crates to get a feel for it, because I think it's still nicer to see that list at the left than to have to go all the way to the bottom of a long readme to find it. In any case on the standard library a foldable outline is top! I feel like I "see" the standard library for the first time! It makes me want to browse it to discover it. Rustdoc never did that for me, thanks!
- Inclusion of the book. It would need a good UI design, but I can totally see it being integrated in the api docs (I mean even the other books, reference, nomicon, rust by example, ...) Eg a really integrated total documentation of rust in one interface. There could be links between the api docs and guide level documentation for more examples, explanation, ... It would also be nice if crates could easily include a user guide straight in the api docs.
Things I don't like:
- Rust being a type strict language I really want to see the declaration of the type. I think it's nice of rustdoc to show that all the way at the top. It's what I look at most.
- Look and feel. A lot of work there, but that's ok for POC. I do like the look and feel of rustdoc + ayu-dark.
- fluidity. On my wide screen there is a whole empty area on the right. Ideally there is a well thought out design for every level, from a phone to a 4k screen that really makes good use of all the available screen space.
- I like alphabetic sorting, but I think I would like at least a button that let's you order and group by implemented traits.
- Not quite sure of the usefulness of the long methods tab. I think I would be more in favor of clicking in the item list folds open a section for the item, pushing escape closes it again. Btw I would do thing like links to the books in a similar way, overlay, so you can read and browse, escape it hides again and you are still in the api docs where you left of.
Ok, there is surely a lot more to say, but I'll leave that to others.