owning-ref-rs VS cxx20-modules-examples

Increasingly feeling that Rust is like Elm: a language with novel ideas, teaching valuable lessons (a vocabulary for teaching and checking thread safety, documenting exclusive vs. shared mutability in the type system, arguably a vocabulary for teaching and checking memory safety, though that comes at a steep cost), yet so stubborn the community treats its values (avoiding shared mutability) as moral judgments of code, and the language and deliberately obstructs writing code outside of approved patterns (single ownership tree, exclusive mutability). struct{Cell...}& doesn't need to be harder to use than C++ struct{T...}*, but Rust keeps it difficult because the community views it as bad code design and wants to keep it hard. And *mut T lacks RAII unlike C++'s unique_ptr, and requires unsafe blocks in every dereference. As a result, people turn to unsound patterns like https://github.com/kimundi/owning-ref-rs, https://github.com/mcoblenz/Bronze/, and https://github.com/emu-rs/snes-apu/blob/master/src/smp.rs#L5....

It's a good language to learn. I hesitate to consider it a replacement for asm/C/C++. Writing rust is hoping that the code you're porting to rust can adapt well to the restrictions, and if not, searching for esoteric and needlessly unsafe/verbose workarounds.

Note that there are other soundness issues that require more fundamental changes to be fixed.

That's a shame. I dug into owning_ref, and it looks like it has an open soundness bug as well.

build2 use the module mapper API which was available long before 2021: https://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Module-Mapper... You can try the examples here https://github.com/build2/cxx20-modules-examples/ with GCC 13 or 12 to confirm, if you wish.

> given communication APIs for GCC just landed in its main branch a month ago

Can you elaborate on what are these "communication APIs"?

It you are looking for news on C++20 modules support, then sadly, there is not much progress since GCC 11. I've re-tested my modules examples[1] a few days ago with the GCC 12 snapshot, and while a few bugs have been fixed, the majority remain unfixed[2].

[1] https://github.com/build2/cxx20-modules-examples

[2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103524

I used a build2 repository containing C++20 Modules hello-world projects setup in different scenario with module partitions, without partitions, libraries or not etc. They all just print hello world but the point is to check and show very basic modules usage.

If anyone is looking for a build system to try C++20 modules with GCC, there is build2: https://build2.org/blog/build2-cxx20-modules-gcc.xhtml

There is also a repository of module examples (some trying to imitate real-world usage like distributing modules as part of a library): https://github.com/build2/cxx20-modules-examples/

Here is a set of examples that exercises major modules features: https://github.com/build2/cxx20-modules-examples