Are We Modules Yet?

Who all are doing the `areweyet` Web sites, other than Rust and this C++ one?

Some notes:

This website scrapes vcpkg's registry[1], which contains many C libraries which are unlikely to ever receive C++20 module updates. Many are primarily binary executable packages, like lunarg-vulkantools. It is quite unfair to judge C++ module support by this. There are even bugs in the table: the issue tracking Vulkan-Hpp module links to https://github.com/KhronosGroup/Vulkan-Hpp/issues/121, but it was actually implemented in https://github.com/KhronosGroup/Vulkan-Hpp/issues/1580 (full disclosure: I implemented it).

Boost maintainers have picked up on this[2], which is big.

The big 3 compilers have had a myriad of bugs, ICEs, and redefinition errors, despite what is claimed on cppreference[3]. VS 2022 17.10 will only just fix some of these, and G++'s module support isn't even released yet. Clang 18 has seemingly full(er) support for C++20 modules, but clangd is broken, and it seems mixing standard library headers and `import std` might still break, as will header units (`import `).

CMake released C++20 modules support with 3.28, and will release `import std` support with 3.30.

This is painful but IMO worth the paper cuts that the bleeding-edge adopters will experience in the next year or so as modules are implemented.

I fully believe that a good one-third to half of build time and power consumption in the past 40+ years of compiling C and C++ code (considerably more so in the case of template-heavy C++ header-only libraries and projects) has gone to parsing and re-parsing headers and the resultant output.

Headers are a distinctly 1970s approach to compartmentalisation. Other languages have sorted dependency and library/import resolution years ago; there's no reason the C and C++ world has to be stuck with essentially copy-pasting code over and over. The embarrassingly parallel building that results from headers is fake; it takes more time and more energy than strictly necessary.

[1]: https://vcpkg.link/browse/all

[2]: https://anarthal.github.io/cppblog/modules

[3]: https://en.cppreference.com/w/cpp/compiler_support/20

Standard library support is not there in any meaningful way across compilers, I fail to see why anyone would adopt modules at the present. MSVC is the furthest along in its support last I looked. Once compiler support is available, I would expect usage to increase fairly rapidly. As with many things C++, modules are a nice-to-have, adopting a successful strategy from other languages/ecosystems, and many will choose to never adopt them.

You know any other language that uses the header/cpp split likes C/C++ do?

This is C++es way of finally getting rid of them, akin to Swift or Rust.

It is a Mozilla culture thing that turned into a Rust thing, and yeah this is the first one I’ve seen outside of those two general communities so far.

Here is my, uh, “favorite” https://arewereorganizedyet.com/