MIO VS rustfmt

Was playing around with mio (https://github.com/tokio-rs/mio) (not that mio itself is very important here!) and was trying to implement a simple something that I've done in java before: a Reactor that you can register ReactorClients with that will get callback whenever there are events on the corresponding socket etc.

How does it compare to mio?

TcpStream gets its wake behavior by delegating to the fd wakers. The Unix wakers have a few implementations, for different platforms. On Linux and Android, epoll is used.

The real implementation details of the I/O event queue is done in mio as u/hniksic pointed out, but that's more comparable with libuv which is certainly a huge part of the Node runtime. mio and libuv have a lot of similarities (at least they used to).

My example was "twice by one developer", not "twice across all indexed repos."

A spot check shows that quite a few in your link are used specifically to ensure correct handling of Rust multi-level breaks work syntax, like https://github.com/rust-lang/rust-analyzer/blob/master/crate... , https://github.com/rust-lang/rustfmt/blob/master/tests/sourc... , https://github.com/rust-lang/rust/blob/master/src/tools/rust... , https://github.com/rust-lang/rust/blob/master/src/tools/rust... and likely more.

Another is a translation of BASIC code to Rust, using break as a form of goto. https://github.com/coding-horror/basic-computer-games/blob/e...

The example at https://github.com/tokio-rs/mio/blob/master/tests/tcp.rs is a nice one

    // Wait for our TCP stream to connect

In my program, I have about 6 different components that follow the pattern below. Basically, the components run a thread while polling on crossbeam channels, file descriptors or sockets. For polling, I am using Mio (https://github.com/tokio-rs/mio).

On the code side it's pretty much the same as C++. You have a module that defines an interface and per-platform implementations that are included depending on a "configuration conditional checks" #[cfg(target_os = "linux")] macro.

https://github.com/tokio-rs/mio/blob/c6b5f13adf67483d927b176...

Made possible by Wasi support for Mio https://github.com/tokio-rs/mio/pull/1576

Indeed! In practice it's done through the polling operation: instead of a separate poll for op1 and op2, the program essentially tells the OS "wake me when either op1 or op2 is ready" (through the epoll syscall on Linux). The mio crate implements this, and the example on the readme is basically the same loop, but written with this polling strategy in mind.

The author provides very surface-level criticism of two Rust tools, but they don't look into why those choices were made.

With about five minutes of my time, I found out:

wrap_comments was introduced in 2019 [0]. There are bugs in the implementation (it breaks Markdown tables), so the option hasn't been marked as stable. Progress on the issue has been spotty.

--no-merge-sources is not trivial to re-implement [1]. The author has already explained why the flag no longer works -- Cargo integrated the command, but not all of the flags. This commit [2] explains why this functionality was removed in the first place.

Rust is open source, so the author of this blog post could improve the state of the software they care about by championing these issues. The --no-merge-sources error message even encourages you to open an issue, presumably so that the authors of Cargo can gauge the importance of certain flags/features.

You could even do something much simpler, like adding a comment to the related issues mentioning that you ran into these rough edges and that it made your life a little worse, or with a workaround that you found.

Alternatively, you can continue to write about how much free software sucks.

[0]: https://github.com/rust-lang/rustfmt/issues/3347

[1]: https://github.com/rust-lang/cargo/pull/10344

[2]: https://github.com/rust-lang/cargo/commit/3842d8e6f20067f716...

The new style still supports single line let-else, and there is a configuration parameter to make it be on one line also for longer lines.

It seems there is an issue about this dating all the way back from 2018 but yet it still hasn't been fixed.

However since 4179 recent versions should merge configuration files. Not sure what the details / specifics are but if just ignoring the file entirely is not good enough you might give it its own directory and rustfmt.toml file and see if that works.

Could this be be #3863 - Gives up on chains if any line is too long? It might not be, because I can't see a specific "line" that's too long to format, but there's more detail about the exact problem in the issue.

Rustfmt is a tool that formats Rust code in compliance with style guidelines. Its name precisely reflects its purpose. To install rustfmt, you can run rustup component add rustfmt. Once installed, you can execute cargo fmt to format Rust code in your workspace. If you require further information, you can visit rustfmt’s GitHub repository.

code must be formatted with rustfmt.

Yes, some cases are not yet supported (https://github.com/rust-lang/rustfmt/issues/4914).

Just FYI, the let-else suggestions will only work until rustfmt settles on a format for it. So you may be surprised when this happens and it suddenly changes.