draft VS ocaml

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

> OCaml’s configure script is also “normal”

If that’s this OCaml, it has a configure.ac file in the root directory, which looks suspicious for an Autotools-free package: https://github.com/ocaml/ocaml

You probably already know, but with OCaml 5 the only way to get flamegraphs working is to either:

* use framepointers [1]

* use LBR (but LBR has a limited depth, and may not work on on all CPUs, I'm assuming due to bugs in perf)

* implement some deep changes in how perf works to handle the 2 stacks in OCaml (I don't even know if this would be possible), or write/adapt some eBPF code to do it

OCaml 5 has a separate stack for OCaml code and C code, and although GDB can link them based on DWARF info, perf DWARF call-graphs cannot (https://github.com/ocaml/ocaml/issues/12563#issuecomment-193...)

If you need more evidence to keep it enabled in future releases, you can use OCaml 5 as an example (unfortunately there aren't many OCaml applications, so that may not carry too much weight on its own).

[1]: I haven't actually realised that Fedora39 has already enabled FP by default, nice! (I still do most of my day-to-day profiling on an ~CentOS 7 system with 'perf --call-graph dwarf', I was aware that there was a discussion to enable FP by default, but haven't noticed it has actually been done already)

11. OCaml - $91,026

> It partially helps since it forces you to have types where they matters most: exported functions

But the problém the OP has is not knowing the types when reading the source (in the .ml file).

> How would it feels like to use list if only https://github.com/ocaml/ocaml/blob/trunk/stdlib/list.ml was available,

If the signature where in the source file (which you can do in OCaml too), there would be no problem - which is what all the other (for some definition of "other") languages except C and C++ (even Fortran) do.

No, really, I can't see a single advantage of separate .mli files at all. The real problém is that the documentation is often worse too, as the .mli is autogenerated and documented afterwards - and now changes made later in the sources need to be documented in the mli too, so anything that doesn't change the type often gets lost. The same happens in C and C++ with header files.

If you have been in the Ruby community for the past couple of years, it's possible that you're not a super fan of types or that this concept never passed through your mind, and that's totally cool. I myself love the dynamic and meta-programming nature of Ruby, and honestly, by the time of this article's writing, we aren't on the level of OCaml for type checking and inference, but still, there are a couple of nice things that types with sorbet bring to the table:

Looks like there have been proposals to eliminate use of 3 operand lea in OCaml code (not accepted sadly):

https://github.com/ocaml/ocaml/pull/8531

An amazing example is Ocaml lang logo / mascot. It might be useful to talk with them to know what was the process behind this work. The About page camel head on Perl dot org header is also a pretty good example of simplification, but it's not a logo, just a friendly illustration, as the O'Reilly camel is. Another notable logo for this animal is the well known tobacco industry company, but don't get me started on that (“good” logo, though, if we look at the effectiveness of their marketing).

Haskell and Agda are probably the most obvious examples. Ocaml too, but it is much older, so its type system is not as categorical. There is also Idris, which is not as well-known but is very cool.

That does sound problematic, but without the code it is hard to tell what is the issue. Typically, compiling a 6kLoc file like https://github.com/ocaml/ocaml/blob/trunk/typing/typecore.ml takes 0.8 s on my machine.