draft VS Asciidoctor

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

You have also AsciiDoctor ( https://asciidoctor.org/ ) which is alive and well. I am using it for technical CS documentation internally, but only for single page documents. I did not try to deploy their whole multi-document setup called Antora ( https://antora.org/ ).

AsciiDoc File support. ( #1876, #808, #2022)

If Maths is important to you, take a look at Asciidoc - https://asciidoctor.org/

I use Asciidoctor, highlightjs, a custom highlight.js language definition and that bash script:

AsciiDoc is so close to being good. It slam dunks Markdown, but they just have a few nagging issues that they refuse to fix, for 9 years now:

https://github.com/asciidoctor/asciidoctor/issues/1087

Asciidoctor is a Ruby-based text processor for parsing AsciiDoc into a document model and converting it to HTML5, PDF, EPUB3, and other formats. Built-in converters for HTML5, DocBook5, and man pages are available in Asciidoctor. Asciidoctor has an out-of-the-box default stylesheet and built-in integrations for MathJax (display beautiful math in your browser), highlight.js, Rouge, and Pygments (syntax highlighting), as well as Font Awesome (for icons). Although Asciidoctor is written in Ruby, that does not mean you need to know Ruby to use it. Asciidoctor can be executed on a JVM using AsciidoctorJ or in any JavaScript environment (including the browser) using Asciidoctor.js. You can choose any one of three Asciidoctor processors (Ruby, JavaScript, Java/JVM) and get the same experience. You can also use the Asciidoctor Maven Plugin to convert your Asciidoc documentation using Asciidoctor from an Apache Maven build.

asciidoctor for writing

If you're looking at AsciiDoc, you'll want to look at Asciidoctor: https://asciidoctor.org/

The third system that I found was AsciiDoc, which started as a Python project, abandoned for a while and eventually resurrected by Dan Allen with Asciidoctor. AsciiDoc has a lot of features and I consider it superior to Markdown, but Asciidoctor is a Ruby program, and this made it difficult for me to use it. In addition, the standard output of Asciidoctor is a nice single HTML page but again customising it is a pain. I eventually created the site of the book using it, but adding my Google Analytics code and a sitemap.xml to the HTML wasn't trivial, not to mention customising the look of elements such as admonitions.