1) Game: A Chinese/Vietnam game with C/C++ for making server/client, Lua for scripting [1]. 2) Embedded systems: Switch/router with network stack all written in C [2]. 3) (Networked) file system: Ceph FS client, which is a kernel module. [3]
(I left some unnecessary details in links, but are true projects I used to work on.)
Recently, there's a hot topic about Rust and C in kernel and a message [4] just draws my attention, where it talks about the "Rust" experiment in kernel development:
> I'd like to understand what the goal of this Rust "experiment" is: If we want to fix existing issues with memory safety we need to do that for existing code and find ways to retrofit it.
So for many years, I keep thinking about having a new C dialect for retrofitting the problems, but of C itself.
Sometimes big systems and software (e.g. OS, browsers, databases) could be made entirely in different languages like C++, Rust, D, Zig, etc. But typically, like I slightly mentioned above, making a good filesystem client requires one to write kernel modules (i.e. to provide a VFS implementation. I do know FUSE, but I believe it's better if one could use VFS directly), it's not always feasible to switch languages.
And I still love C, for its unique "bare-bone" experience:
1) Just talk to the platform, almost all the platforms speak C. Nothing like Rust's PAL (platform-agnostic layer) is needed. 2) Just talk to other languages, C is the lingua franca (except Go needs no libc by default). Not to mention if I want WebAssembly to talk to Rust, `extern "C"` is need in Rust code. 3) Just a libc, widely available, write my own data structures carefully. Since usually one is writing some critical components of a bigger system in C, it's just okay there are not many choices of existing libraries to use. 4) I don't need an over-generalized generics functionality, use of generics is quite limited.
So unlike a few `unsafe` in a safe Rust, I want something like a few "safe" in an ambient "unsafe" C dialect. But I'm not saying "unsafe" is good or bad, I'm saying that "don't talk about unsafe vs safe", it's C itself, you wouldn't say anything is "safe" or "unsafe" in C.
Actually I'm also an expert on implementing advanced type systems, some of my works include:
1) A row-polymorphic JavaScript dialect [5]. 2) A tiny theorem prover with Lean 4 syntax in less than 1K LOC [6]. 3) A Rust dialect with reuse analysis [7].
Language features like generics, compile-time eval, trait/typeclass, bidirectional typechecking are trivial for me, I successfully implemented them above.
For the retrofitted C, these features initially come to my mind:
1) Code generation directly to C, no LLVM IR, no machine code. 2) Module, like C++20 module, to eliminate use of headers. 3) Compile-time eval, type-level computation, like `malloc(int)` is actually a thing. 4) Tactics-like metaprogramming to generate definitions, acting like type-safe macros. 5) Quantitative types [8] to track the use of resources (pointers, FDs). The typechecker tells the user how to insert `free` in all possible positions, don't do anything like RAII. 6) Limited lifetime checking, but some people tells me lifetime is not needed in such a language.
Any further insights? Shall I kickstart such project? Please I need your ideas very much.
[1]: https://vi.wikipedia.org/wiki/V%C3%B5_L%C3%A2m_Truy%E1%BB%81...
[2]: https://e.huawei.com/en/products/optical-access/ma5800
[3]: https://docs.ceph.com/en/reef/cephfs/
[4]: https://lore.kernel.org/rust-for-linux/Z7SwcnUzjZYfuJ4-@infr...
[5]: https://github.com/rowscript/rowscript
[6]: https://github.com/anqurvanillapy/TinyLean