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Boost downloads and JFrog
by Glen Fernandes 13 Jan '24

13 Jan '24

Rather than emails and Slack DMs, I would prefer we have this discussion on the mailing list. To summarize what I have repeated in the aforementioned channels: - Yes, our downloads are not working again because the JFrog account is again not active. - No, I cannot do anything about the JFrog account. - Yes, we can update the website to point to downloads hosted elsewhere. It is correct that JFrog does not charge us yet but our traffic has increased from 60TB/month to almost 200TB/month which is no longer supportable for free. We have limited time to find a solution. We are on borrowed time but as far as I know we still have time. the deactivation of the JFrog account in December 31 was not expected, and it was reinstated. Glen

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Request for comments: to_static_string
by Ruben Perez 13 Jan '24

13 Jan '24

Hi all, Since we will be reviewing Boost.CharConv shortly, and my development efforts in Boost.MySQL are currently requiring converting numbers to strings, I've been playing with the utilities we currently have to do so. I've found cases where I just needed to convert something to string, then pass the result to another function taking a string_view as parameter. The most efficient and correct way to do so is using to_chars (stack based, non-throwing, C++23 constexpr and locale-independent). But I still like the simplicity of std::to_string. Since I had some free time this weekend, I took a step forward and implemented a (deadly simple) wrapper around to_chars that looks like std::to_string, but has all the benefits of to_chars. I called this to_static_string. Repo is here: https://github.com/anarthal/to-static-string This is currently a prototype. I want to hear everyone's opinion on this - do you think this may be useful to any of you? I don't think it's big enough to even consider putting it into Boost (my idea is having it as a standalone lib). Any comments are welcome. Thanks, Ruben.

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[scope] Some random thoughts
by Andrzej Krzemienski 10 Jan '24

10 Jan '24

Hi All, Two observations from reading the docs. Why do I need a condition in scope_exit when I have a scope_fail? I recommend putting warning somewhere in the docs that while using scope guards you may inadvertently read an object after move: std::string checked(std::string name) { scope::scope_exit g{[&]{ std::clog << "checked " << name <<std::endl; }}; validate(name); return name; // name becomes moved-from } Regards, &rzej;

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Forthcoming Boost.Charconv review January 15th - 25th, 2024
by Christopher Kormanyos 09 Jan '24

09 Jan '24

Dear all, The review of Boost.Charconv by Matt Borland is scheduledfrom Monday, January 15th to January 25th, 2024. ----------------------------------------------------- About the library: Boost.Charconv provides a highly portable and efficient, C++11 implementation of <charconv>. The API containsfunctions compatible with <charconv>. Boost.Charconv can be highly useful for portability and efficiency. The standard library's <charconv> requires C++17 or higher. Currently only quite modern compilers such as GCC 11+ and MSVC 19.24+ support both integer and floating-point conversions in their implementation of <charconv>. If you are using either of those compilers, Boost.Charconv is at least as performant as <charconv>, and can be up to several times faster. If you are using an older compiler or a language standard lower than C++17, then there is no <charconv> available. In such cases, Boost.Charconv provides a highly-viable, portable and efficient header-only implementation. Boost.Charconv is a compiled library and does require a few other Boost libraries to run. The docs providedirections for how to consume with b2, vcpkg and Conanto facilitate this. Boost.Charconv fits into Boost stylistically and through itshigh quality, its Boost-like testing and its documentation. Boost.Charconv has been well-received and endorsed on the Boost-lists and is already being used for prototyping in several existing Boost libraries. Tool vendors have expressed interest in Boost.Charconv particularly due to its high performance and clarity of implementation details. docs: https://develop.charconv.cpp.al git: https://github.com/cppalliance/charconv --------------------------------------------------- Naturally, you need not wait until the review formally opens to start reviewing the Charconv library. Please always state in your review whether you think the library should be accepted as a Boost library! Please consider giving feedback on the following general topics: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? Christopher Kormanyos Boost.Charconv Review Manager ------------------------------

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boost.sqlite
by Klemens Morgenstern 06 Jan '24

06 Jan '24

I've written a boost.sqlite library last year mainly to experiment, but it has been a feature-complete C++ wrapper for a while. Hence I'd like to gauge interest to see if it's worth proposing for boost. It has more features than most C++ sqlite wrappers and uses boost-isms such as system.result, tag_invoke and boost.json. Code: https://github.com/klemens-morgenstern/sqlite Docs: https://klemens.dev/sqlite/

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Re: [boost] Interest in new parsing library?
by tobi＠die-loews.de 06 Jan '24

06 Jan '24

Zach Laine wrote: > - use approximately the same set of directives to influence the parse > (e.g. lexeme[]); It seems there is no directive like Spirit's no_case. Is there a way to match case-insensitivity?

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Google Summar of Code 2024 - Collecting Projects & Mentors! 📢
by Inbal Levi 05 Jan '24

05 Jan '24

Hello all! We would like to collect projects & mentors for the GSOC 2024 :) If you would like to volunteer as a mentor and/or have a proposal for a Boost project which you like to collect volunteers for, please fill in the proper tab: https://docs.google.com/spreadsheets/d/1_eUWRsXnhi_JwKZbHZsGQf3WNUESsAPE4lV… Once we have a list of proposed projects, we will upload them to GitHub. Thanks! Best regards, Inbal Levi ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ *Lead Software Engineer @ Millenium* Isocpp, Boost &"Hamakor" Non-Profits Board Member ISO C++ LEWG Chair & Israeli NB Chair C++Now Program Chair & CoreC++ Conference Organizer ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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Recommendations for documentation authors
by Andrzej Krzemienski 04 Jan '24

04 Jan '24

Hi Boost Developers, And a happy New Year (at least for those who recognize the Gregorian calendar). While I consider improving the documentation quality of some Boost libraries, I wonder if there are any tool or workflow recommendations for the library authors regarding the documentation. I know we do not force any specific tool or format, so I am only asking about recommendations. I note that page https://www.preview.boost.org has at https://www.preview.boost.org/doc/contributor-guide/docs/documentation-guid… the following: > The format for documentation on the new website is AsciiDoc Syntax Quick Reference <https://docs.asciidoctor.org/asciidoc/latest/syntax-quick-reference/>. Should I treat it as a recommendation to use AsciiDoc? I note that quite a few new libraries choose it. I also see the advantage: you need no special tool for it: a simple web browser knows how to format it. But I found the documentation of libraries that use adoc to be uncomfortable to read. I do not know if this is the tool itself or maybe the correlation between the choice of the tool and the devotion to documentation quality, or maybe something else. It is quite subjective. The older libraries' documentation (using BoostDoc) seemed more friendly and easier to navigate. But to write and maintain such documentation is a challenge. Last year something broke in my pipeline (QuickDoc, xstlproc) and to this day I am not able to determine what it is. So, relying on too complex flows, which become obsolete over time, also doesn't seem like a good idea. I wonder if any of you have similar thoughts, and if you can recommend something for writing good quality and user friendly documentation. Regards, &rzej;

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[website][string_ref] Broken link to the library docs
by Andrey Semashev 02 Jan '24

02 Jan '24

Hi, In the library list for Boost 1.84: https://www.boost.org/doc/libs/1_84_0/ there is an entry for Boost.StringRef. However, that library was removed from libs/utility/meta/libraries.json. Or, more precisely, it was renamed to Boost.StringView (key: utility/string_view). The problem is that the StringRef entry in the above list has a broken link to the library docs, and the rename was supposed to fix it (by having an entry for StringView instead, linking to its docs). I'm not sure where StringRef comes from, but can it be removed? This has been reported a few times already: https://github.com/boostorg/website/issues/763 https://github.com/boostorg/utility/issues/105

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Interest in new parsing library?
by Zach Laine 30 Dec '23

30 Dec '23

I'm trying to gauge interest in a parsing library to replace Boost.Spirit 2/Spirit X3. I'm also looking for endorsements. The library is intended to remedy some shortcomings of Boost.Spirit*. I think these are great libraries, but Spirit 2 was written in pre-11 C++ (I think; certainly its dependencies were). Most-to-all of the downsides stem from that -- long compile times, inscrutable compilation failures, etc. (Boost.Parser compile times are quite low.) I'm calling my proposal Boost.Parser, and it follows many of the conventions of Boost.Spirit 2 and X3, such as the operators used for overloading, the names of many parsers and directives, etc. It requires C++17 or later. >From the introduction in the online docs: """ Boost.Parser is a parser combinator library. That is, it consists of a set of low-level primitive parsers, and operations that can be used to combine those parsers into more complicated parsers. There are primitive parsers that parse epsilon (the empty string), chars, ints, floats, etc. There are operations which combine parsers to create new parsers. For instance, the Kleene star operation takes an existing parser p and creates a new parser that matches zero or more occurrences of whatever p matches. Both callable objects and operator overloads are used for the combining operations. For instance, operator*() is used for Kleene star, and you can also write repeat(n)[p] to create a parser for exactly n repetitions of p. Boost.Parser also tries to accommodate the multiple ways that people often want to get a parse result out of their parsing code. Some parsing may best be done by returning an object that represents the result of the parse. Other parsing may best be done by filling in a preexisting data structure. Yet other parsing may best be done by parsing small sections of a large document, and reporting the results of subparsers as they are finished, via callbacks. Boost.Parser accommodates all these ways of working, and even makes it possible to do callback-based or non-callback-based parsing without rewriting any code (except by changing the top-level call from parse() to callback_parse()). All of Boost.Parser's public interfaces are sentinel- and range-friendly, just like the interfaces in std::ranges. Boost.Parser is Unicode-aware through and through. When you parse ranges of char, Boost.Parser does not assume any particular encoding — not Unicode or any other encoding. Parsing of inputs other than plain chars assumes that the input is Unicode. In the Unicode-aware code paths, all parsing is done by matching code points. This means that you can feed UTF-8 strings into Boost.Parser, both as input and within your parser, and the right sort of matching occurs. For instance, if your parser is trying to match repetitions of the char '\xcc' (which is a lead byte from a UTF-8 sequence, and so is malformed UTF-8 if not followed by an appropriate UTF-8 code unit), it will not match the start of "\xcc\x80" (UTF-8 for the code point U+0300). Boost.Parser knows that the matching must be whole-code-point, and so it interprets the char '\xcc' as the code point U+00CC. Error reporting is important to get right, and it is important to make errors easy to understand, especially for end-users. Boost.Parser produces runtime parse error messages that are very similar to the diagnostics that you get when compiling with GCC and Clang (it even supports warnings that don't fail the parse). The exact token associated with a diagnostic can be reported to the user, with the containing line quoted, and with a marker pointing right at the token. Boost.Parser takes care of this for you; your parser does not need to include any special code to make this happen. Of course, you can also replace the error handler entirely, if it doesn't fit your needs. Debugging complex parsers can be a real nightmare. Boost.Parser makes it trivial to get a trace of your entire parse, with easy-to-read (and very verbose) indications of where each part of the trace is within the parse, the state of values produced by the parse, etc. Again, you don't need to write any code to make this happen — you just pass a parameter to parse(). Dependencies are still a nightmare in C++, so Boost.Parser can be used as a purely standalone library, independent of Boost. """ Boost.Parser aims to be a superset of Boost.Spriit* in most ways. Major things missing from the set of features in Spirit 2 + Spirit X3 are: - A separate lexer. - Binary parsers (meaning for parsing bits, not binary numbers written as text; the latter is fully supported). I've been in touch with Joel de Guzman, Hartmut Kaiser, and Michael Caisse, to make sure I was not toe-stomping, for those who are concerned about that. They gave this new library their blessing. One feature comes entirely from them: Boost.Parser is usable in a Boost-free environment -- as a standalone library -- at the user's option. They said that was the #1 request from users, which surprised me a bit. The Github page is here: https://github.com/tzlaine/parser The online docs are here: https://tzlaine.github.io/parser To see an extended example, here's a JSON parser that passes all the published JSON tests, including most of the optional ones, in only about 300 lines of code, go here: https://tzlaine.github.io/parser/doc/html/boost_parser__proposed_/extended_… Finally, for those wanting to know how this lib differs from Boost.Spirit* without digging through the docs, here is the doc page that explains Boost.Parser's relationship to Boost.Spirit*: """ Boost.Spirit is a library that is already in Boost, and it has been around for a long time. However, it does not suit user needs in some ways. Spirit 2 suffers from very long compile times. Spirit 2 has error reporting that requires a lot of user intervention to work. Spirit 2 requires user intervention, including a (long) recompile, to enable parse tracing. Spirit X3 has rules that do not compose well — the attributes produced by a rule can change depending on the context in which you use the rule. Spirit X3 is missing many of the convenient interfaces to parsers that Spirit 2 had. For instance, you cannot add parameters to a parser. All versions of Spirit have Unicode support, but it is quite difficult to get working. I wanted a library that does not suffer from any of the above limitations. It should be noted that while Spirit X3 only has a couple of flaws in the list above, the one related to rules is a deal-breaker. The ability to write rules, test them in isolation, and then re-use them throughout a complex parser is essential. Though no version of Boost.Spirit (Spirit 2 or Spirit X3) suffers from all those limitations, there also does not exist any one version that avoids all of them. Boost.Parser does so. However, there are a lot of great ideas in Boost.Spirit that have been retained in Boost.Parser. Both libraries: - use the same operator overloads to combine parsers; - use approximately the same set of directives to influence the parse (e.g. lexeme[]); - provide loosely-coupled rules that are separately compilable (at least for Spirit X3); and - are built around a flexible parse context object that has state added to and removed from it during the parse (again, comparing to Spirit X3). """ Zach

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