Re: [PATCH 1/7] rust: file: add Rust abstraction for `struct file`

[Peter Zijlstra <peterz@infradead.org>]

On Fri, Dec 01, 2023 at 02:36:40AM -0800, Boqun Feng wrote:

> I don't speak for the Rust langauge community, but I think this is
> something that they should improve. I understand it could be frustrating
> that we find out the new stuff doesn't support good old tools we use
> (trust me, I do!), but I believe you also understand that a higher level
> language can help in some places, for example, SBRM is naturally
> supported ;-) This answers half of the question: "Why are we even trying
> to use it again?".

C++ does that too (and a ton of other languages), and has a much less
craptastic syntax (not claiming C++ syntax doesn't have problems, but at
least its the same language family). Now I realize C++ isn't ideal, it
inherits much of the safety issues from C. But gah, rust is such a royal
pain.

> The other half is how languages are designed is different in these days:
> a language community may do a better job on listening to the users and
> the real use cases can affect the language design in return. While we
> are doing our own experiment, we might well give that a shot too.

Well, rust was clearly not designed to interact with C/C++ sanely. Given
the kernel is a giant C project, this is somewhat of an issue IMO.

IIRC the way Chrome makes it work with C++ is by defining the interface
in a *third* language which compiles into 'compatible' Rust and C++,
which is total idiocy if you ask me.

Some langauges (Zig IIUC) can consume regular C headers and are much
less painful to interact with (I know very little about Zig, no
endorsement beyond it integrating much better with C).

> And at least the document admits these are "future possibilities", so
> they should be more motivated to implement these.
> 
> It's never perfect, but we gotta start somewhere.

How about they start by using this LLVM goodness to implement the rust
equivalent of Zig's @cImport? Have it use clang to munge the C/C++
headers into IR and squash the lot into the rust thing.

The syntax is ofcourse unfixable :-(