[viktorcode]

> We previously explored Swift, but the C++ interop never quite got there

But Rust doesn't have C++ interop at all?

[nicoburns]

You can do it via the C ABI, and use opaque pointers to represent higher-level Rust/C++ concepts if you want to.

Firefox is a mixed C++ / Rust codebase with a relatively close coupling between Rust and C++ components in places (layout/dom/script are in C++ while style is in Rust, and a mix of WebRender (Rust) and Skia (C++) are used for rendering with C++ glue code)

[wavemode]

> You can do it via the C ABI, and use opaque pointers to represent higher-level Rust/C++ concepts

Yeah but, you can do the same in Swift

[tonyedgecombe]

>But Rust doesn't have C++ interop at all?

It also doesn't have the disadvantages of Swift. Once the promise of Swift/C++ interop is gone there isn't enough left to recommend it.

[skavi]

I’m curious what issues people were running into with Swift’s built in C++ interop? I haven’t had the chance to use it myself, but it seemed reasonable to me at a surface level.

[woadwarrior01]

Yeah, that part doesn't make much sense to me. IMO, Swift has reasonably good C++ interop[1] and Swift's C interop has also significantly improved[2] since Swift 6.2.

[1]: https://www.swift.org/documentation/cxx-interop/

[2]: https://www.swift.org/blog/improving-usability-of-c-librarie...

[azornathogron]

It may have in the future. Crubit is one effort in this direction: https://crubit.rs/

[matthewkosarek]

There is also cxx.rs, which is quite nice, albeit you have to struggle sending `std` types back and forth a bit

[nicoburns]

> albeit you have to struggle sending `std` types back and forth a bit

Firefox solves this partly by not using `std` types.

For example, https://github.com/mozilla/thin-vec exists in large part because it's compatible with Firefox's existing C++ Vec/Array implementation (with the bonus that it's only 8 bytes on the stack compared to 24 for the std Vec).

[k33n]

It's technically Rust -> C -> C++ as it stands right now

[the_mitsuhiko]

Rust has cxx which I would argue is "good enough" for most use cases. At least all C++ use cases I have. Not perfect, but pretty damn reasonable.