draft VS rust

I should have said the "latest standard", not "spec", if we're being technical. But EVERY bit of official material is very clear about asserting that C++23 is still a preview/in-progress, not a standard. Saying otherwise is, strictly speaking, incorrect.

https://isocpp.org/std/the-standard

https://www.iso.org/standard/79358.html

https://github.com/cplusplus/draft/blob/main/papers/n4951.md

[3] https://github.com/cplusplus/draft/releases/tag/n4917

*This is a joke, but only barely so.

pdf

I'm currently going through Annex A of C++20, but I can't find the definition of "designator brace-or-equal-initializer", and couldn't find much formal information on it in an obvious way. The newest source on [decl] (https://github.com/cplusplus/draft/blob/main/source/declarations.tex) also doesn't seem to have it. Am I missing anything, or is this a missing definition in the standard grammar?

> I don't have a copy of the standard at hand, can anyone quote the relevant section?

The C++ (draft) standard is on GitHub! [0] Compiling it needs Perl and some LaTeX packages, but is reasonably straightforwards otherwise. In addition, links to specific draft standards can be found on cppreference [1].

But anyways, in the first C++20 post-publication draft (N4868), the wording you're interested in is in multiple sections. Section 22.2.3 Sequence Containers [sequence.reqmts] has Table 78: Optional sequence container operations [tab:container.seq.opt] (starting on page 815), which states that a precondition of pop_back() is that empty() returns false. Section 16.3.2.4 Detailed Specifications [structure.specifications] (page 481) states:

> Preconditions: the conditions that the function assumes to hold whenever it is called; violation of any preconditions results in undefined behavior.

Therefore, calling pop_back() on an empty vector results in undefined behavior.

> Is this something that in practice is implemented in different (exception-throwing) ways?

Based on a quick glance at the major implementations (libc++ 15.0.7 at [2], MSVC at [3], libstdc++ at [4]), it looks like asserts are used. Whether those result in exceptions probably depends on whether the asserts are compiled in in the first place and how they are implemented, but it's definitely not a guaranteed exception.

[0]: https://github.com/cplusplus/draft

[1]: https://en.cppreference.com/w/cpp/links

[2]: https://github.com/llvm/llvm-project/blob/llvmorg-15.0.7/lib...

[3]: https://github.com/llvm/llvm-project/blob/8dfdcc7b7bf66834a7...

[4]: https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=libstdc%2B%2B-v3...

Which standard specifically are you quoting there? I checked an old and a new C++ draft in https://github.com/cplusplus/draft/tree/main/papers, and in neither one did 6.3 have anything like that.

https://github.com/cplusplus/draft/releases/download/n4917/n4917.pdf (page 1, chapter 1 scope):

PRs for C++ are at https://github.com/cplusplus/draft But the discussion for a PR is via https://isocpp.org/std/submit-a-proposal

C/C++

By the way, https://github.com/cplusplus/draft/releases/tag/n4910 , says

If you haven't dipped your touch-typing fingers into Rust yet, you really owe it to yourself. Rust is a modern programming language with features that make it suitable not only for systems programming -- its original purpose, but just about any other environment, too; there are frameworks that let your build web services, web applications including user interfaces, software for embedded devices, machine learning solutions, and of course, command-line tools. Since a custom GitHub Action is essentially a command-line tool that interacts with the system through files and environment variables, Rust is perfectly suited for that as well.

Here's an example of someone citing a disagreement between CRT and shell32:

https://github.com/rust-lang/rust/issues/44650

This in addition to the Rust CVE mentioned elsewhere in the thread which was rooted in this issue:

https://blog.rust-lang.org/2024/04/09/cve-2024-24576.html

Here are some quick programs to test contrasting approaches. I don't have examples of inputs where they parse differently on hand right now, but I know they exist. This was also a problem that was frequently discussed internally when I worked at MSFT.

    #include 

> instead of choosing a certain numbered version of the random library (if I remember correctly) I let cargo download the latest version which had a completely different API.

Yeah, they didn't follow the instructions and got burned. I still think that multiple things went wrong simultaneously for that experience. I wonder if more prevalent uses of `#[doc(alias = "name")]` being leveraged by https://github.com/rust-lang/rust/pull/120730 (which now that I check only accounts for methods and not functions, I should get on that!) so that when changing APIs around people at least get a slightly better experience.

Almost fixed the compiler: https://github.com/rust-lang/rust/pull/123325

Rust: A secure, efficient, and modern programming language (omitting ten thousand words). You can simply follow the installation instructions provided on the official website.

Recently did something similar in Rust but for generating SVGs. We've adopted it for snapshot testing of cargo and rustc's output. Don't have a good PR handy for showing Github's rendering of changes in the SVG (text, side-by-side, swiping) but https://github.com/rust-lang/rust/pull/121877/files has newly added SVGs.

To see what is supported, see the screenshot in the docs: https://docs.rs/anstyle-svg/latest/anstyle_svg/

We strongly believe in Rust as a powerful language for building production-grade software, especially for systems like ours that run alongside Kubernetes.

The above Assert<{N % 2 == 1}> requires #![feature(generic_const_exprs)] and the nightly toolchain. See https://github.com/rust-lang/rust/issues/76560 for more info.