March 2016 - Boost - lists.preview.boost.org

[Block Pointer][Container] Works - Take 2
by Phil Bouchard 06 Mar '16

06 Mar '16

Sorry for all the confusion but I was very confused myself. Now the block_ptr<> works in all cases with Linux x86: - I removed the usage of an allocator. Now there is no need for any allocator anymore. - I removed the usage of the strange pointer proxy optimization. Now the memory manager might take more memory but the class is clean and correctly abstracted. - I removed the usage of weak references. This is just too error-prone. But I need to tell whether an address is on the stack or on the heap. There is no portable way to do this except from marking the heap boundaries by overloading an allocator or write assembly code for each architecture / OS. I prefer the latter and I think this should eventually be part of the standards. Once again the working examples are here: https://github.com/philippeb8/block_ptr/blob/master/example/benchmark.cpp https://github.com/philippeb8/block_ptr/blob/master/example/block_ptr_test1… https://github.com/philippeb8/block_ptr/blob/master/example/block_ptr_test2… Regards, -Phil

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merge to master?
by Robert Ramey 05 Mar '16

05 Mar '16

I've (finally!) got the latest version of the serialization library to pass all the tests on develop. I would like to merge develop to master. May I do this? Robert Ramey

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[Block.Pointer][Container] Works!
by Phil Bouchard 05 Mar '16

05 Mar '16

Ok now everything works!! https://github.com/philippeb8/block_ptr/blob/master/example/block_ptr_test2… So now block_ptr<> is Boost.Container compliant! I still need to fix an issue but it's moving forward! Thanks, -Phil

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[test] Boost.Test fails to build with gcc-4.6
by John Maddock 05 Mar '16

05 Mar '16

See http://www.boost.org/development/tests/develop/developer/output/igaztanaga-…

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[Fit] pipable order of the arguments
by Vicente J. Botet Escriba 05 Mar '16

05 Mar '16

Hi, I would like to know what other think about the order of the pipe (See this issue https://github.com/pfultz2/Fit/issues/5) What would be the expected meaning of auto r1 =1 | pipable(f)(2); f(1,2) or f(2,1)? What would be the expected meaning of auto f2 = partial(f)(2); auto r1 =1 | pipable(f2); f(1,2) or f(2,1)? As the operator| has left-to-right associativity, we can not do auto x = 1 | 2 | pipable(f); We would need a way to pack the parameters auto x = forward_as_tuple(1, 2) | pipable(f); but this wouldn't compile as f has two parameters. or use parenthesis auto x = 1 | (2 | pipable(f)); and the result will be f(2, 1). Any ideas? Best, Vicente Vicente

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[fusion] getting type of attribute_proxy for BOOST_FUSION_ADAPT_ADT
by Jens Weller 05 Mar '16

05 Mar '16

Hello, Code below, first what I'm trying to do is... assign a value to a adapted struct (BOOST_FUSION_ADAPT_ADT), which works fine if both are of the same type or convertible: template<int I, class Seq, class V> typename std::enable_if< std::is_convertible< typename fusion::result_of::at_c<Seq, I>::type, V>::value ,void>::type assign(Seq& s, V& v) { fusion::get<I>(s) = v; } Some of my input is string, and the struct member is bool, unsigned int etc. In this case I'd need to know the type to convert from string. boost::fusion::get returns the attribute_proxy for the adapted struct, so does at_c<>::type. template<int I, class Seq, class V> typename std::enable_if< !std::is_convertible< typename fusion::result_of::at_c<Seq, I>::type, V>::value /*&& !std::is_same<typename std::decay<V>::type,std::string>::value*/ ,void>::type assign(Seq& s, V& v) { std::stringstream ss; ss << v; ss >> fusion::get<I>(s); } Obviously this does not compile. Is there any trick to get to the type of the proxy? One idea I have is decltype(fusion::get<I>(s).get()), but not sure if I can get this to work in an enable_if... thanks, Jens Weller

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[operators] permission to merge develop to master
by Daniel Frey 05 Mar '16

05 Mar '16

May I merge the ADL protection from develop to master for utility/operators?

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[optional] Why was optional<T>::reset() deprecated?
by Nevin Liber 04 Mar '16

04 Mar '16

Does anyone know? We are considering adding it to std::optional this week. Thanks, -- Nevin ":-)" Liber <mailto:nevin@cplusplusguy.com <nevin(a)eviloverlord.com>> +1-847-691-1404

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[type_traits] is_base_of<B, D> should work when B is incomplete
by Andrzej Krzemienski 04 Mar '16

04 Mar '16

Hi, I have filed the following ticket: https://svn.boost.org/trac/boost/ticket/12027 The Standard ([meta.rel]) requires that in std::is_base_of<B, D> D must be a complete type, but it does not require the same of B. This makes sense, because if we compare a complete type D and an incomplete type B, the former is surely not derived from the latter. In contrast, boost::is_base_of imposes an additional constraint that B must also be complete. Could this restriction be lifted? Regards, &rzej

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[range] merge to master?
by Jürgen Hunold 04 Mar '16

04 Mar '16

Hi Neil, could you please merge Boost.Range to master? There are some merged PRs fixing bugs in develop which I'd like to see in 1.61.0 Yours, Jürgen -- * Dipl.-Math. Jürgen Hunold ! * voice: ++49 4257 300 ! Fährstraße 1 * fax : ++49 4257 300 ! 31609 Balge/Sebbenhausen * jhunold(a)gmx.eu ! Germany

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Re: [boost] [Fit] upcoming formal review for Boost.Fit
by Bjorn Reese 03 Mar '16

03 Mar '16

On 02/27/2016 05:16 PM, Vicente J. Botet Escriba wrote: > Documentation:http://pfultz2.github.io/Fit/doc/html/ In More Examples / Projections there is this example: std::sort(std::begin(people), std::end(people), by(&Person::year_of_birth, _ < _)); That strikes me as a very terse syntax, where the reader could easily miss the fact that two values are being compared. Have you considered the use of placeholders like _1 and _2 instead?

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[Block.Pointer][Container] List node allocator
by Phil Bouchard 02 Mar '16

02 Mar '16

I've refactored most of the internal algorithms of block_ptr<> and now it is much more robust. The following example works pretty well: https://github.com/philippeb8/block_ptr/blob/master/example/block_ptr_test1… The next step is to support Boost.Containers: https://github.com/philippeb8/block_ptr/blob/master/example/block_ptr_test2… But after debugging the code it looks like the allocator is not used to instantiate the nodes and I do not see how it is used by looking at the code: template <class T, class VoidPointer> struct list_node : public list_hook<VoidPointer>::type { private: //list_node(); public: typedef T value_type; typedef typename list_hook<VoidPointer>::type hook_type; T m_data; T &get_data() { return this->m_data; } const T &get_data() const { return this->m_data; } }; Am I missing something? Thanks a lot for your help, -Phil

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[gsoc16] Boost rejected as GSoC 2016 org
by Niall Douglas 02 Mar '16

02 Mar '16

Dear Boost, It is with a heavy heart I write to say that Boost was rejected as an org for Google Summer of Code 2016 by Google. We had our application submitted in time, it was reviewed by three members of the Boost leadership, our ideas list had six solid ideas with an especially solid seventh on the way, we were in very good standing with Google and there was no reason to expect rejection. We have asked for clarification as to why we were rejected, and we shall try to improve our application next year to improve our chances. We recognise that many students and mentors will be extremely disappointed by this news. We share in that disappointment, and all we can say is please try again next year. For those students and mentors who are continuing a previous GSoC on an existing Boost library, there may be a possibility that Boost may be able to fund those continuations this year. Each case will be approached by the steering committee on a case by case basis, and be aware that the standard required for funding by Boost is considerably above that of Google's with an accompanying high and detailed standard of funding application to the steering committee. Contact us privately if you want to know more. On other news we had been expecting to announce today that Bryce Adelstein Lelbach has generously agreed to take over as secondary GSoC admin from Boris Schäling who has served Boost GSoC for something like four years now, so he has definitely earned himself a rest! Our thanks to Boris for his service, and welcome Bryce to the team! Finally, I'd like to thank Jon Kalb who moved heaven and earth as he always does to get the GSoC application submitted in time. Yours, Niall Douglas -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

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Re: [boost] [gsoc16] An update on GSoC 2016 contingency plans
by Bjorn Reese 02 Mar '16

02 Mar '16

On 03/02/2016 05:17 PM, Niall Douglas wrote: > * Boost.Http, mentored by Bjorn Reese. > https://boostgsoc14.github.io/boost.http/ > > Student: Vinícius dos Santos Oliveira > > Status: One peer review held I have been preparing a proposal for GSoC 2016 which got delayed due to the usual excuses (work-load.) This is a draft of the proposal: Title: HTTP parser combinator. This proposal explores a more flexible HTTP parser framework based on ideas from parser combinators and pull parsers. The framework differentiates itself from the existing HTTP parser libraries for C/C++ on several accounts. With the help of parser combinators it offers the possibility of parsing an entire HTTP message or just a piece of it. The framework should consist of mini-parsers for the individual BNF rules in the HTTP grammar [1]. This is useful when integrating with existing HTTP transport libraries, such as libcurl, which may deliver one HTTP header at the time through a calllback mechanism. Pull parsers gives us the opportunity to replace the parser during the parsing process. This is useful for HTTP Upgrade requests, where the grammar may change "in-flight." For example, WebSockets starts off using the normal HTTP grammar, but then changes to its own binary protocol. Other examples are the differently formatted data that occurs in HTTP messages, such as x-www-form-urlencoded [2] or JSON [3]. Pull parsers also allows for smaller memory footprint. [1] https://tools.ietf.org/html/rfc7230 [2] https://www.w3.org/TR/html401/interact/forms.html#h-17.13.4.1 [3] https://tools.ietf.org/html/rfc7159

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[gsoc16] An update on GSoC 2016 contingency plans
by Niall Douglas 02 Mar '16

02 Mar '16

Dear Boost, We've been collecting a list of veteran Summer of Code students where "veteran" means students whom have previously done a Google Summer of Code for Boost. It /may/ be possible for us to acquire enough funding from a number of contributors to tide over ongoing GSoC projects this summer during our year off from Google funding for veteran students only. The stipend to the student would be the same as with Google, $5,500. The mentor stipend would likely need to be waived under any substitute programme. We would therefore appreciate an update from student and/or mentor as to whether they were intending to submit a continuing GSoC this summer and would be willing to continue work on their Boost library under any funding we find. If we have forgotten any students or projects, please get in touch. Extant ongoing summer of code projects known to us are (please send corrections of any mistakes): * Boost Document, mentored by Antony Polukhin. https://anuragxel.github.io/boost-document/ Student: Anurag Ghosh Status: Not peer reviewed * Boost.Compute, mentored by Kyle Lutz. https://boostorg.github.io/compute/ Student: Jakub Szuppe Status: Official Boost library * Boost.Hana, mentored by Joel Falcou. https://boostorg.github.io/hana/ Student: Louis Dionne Status: Official Boost library * Boost.Http, mentored by Bjorn Reese. https://boostgsoc14.github.io/boost.http/ Student: Vinícius dos Santos Oliveira Status: One peer review held * Boost.Fixed-Point, mentored by Paul Bristow. https://github.com/BoostGSoC15/fixed_point Student: Nikhar Agrawal Status: Not peer reviewed We are aware of the following Boost libraries who have strong but new-to-Boost potential student candidates in the pipeline for summer of code 2016: * Boost.odeint, mentored by Karsten Ahnert and Mario Mulansky There is even less chance we can find funding for these, but if any of the veteran students or mentors has to suddenly pull out before the summer, we would substitute one of these projects instead. Therefore, if mentors had a really excellent student lined up for 2016, please let us know. None of the above should be read that summer of code 2016 is going ahead. We just need some hard numbers with which to lobby for funding. We will get back to the community as soon as we know more. We need all this information requested above back BEFORE this weekend as we will be making use of the Jacksonville ISO WG21 meeting currently happening to grab the right people to ask them for donations from their corporate bodies. If YOUR corporate org would be willing to help sponsor a summer of code student, either partially or in full, PLEASE get in touch. Donations to Boost are tax deductible for US taxpayers. Thank you all very much in advance! Niall --- Boost C++ Libraries Google Summer of Code 2016 admin https://svn.boost.org/trac/boost/wiki/SoC2016

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[serialization] Back Versioning issue
by Janusz Zradomia 02 Mar '16

02 Mar '16

We want to use boost::serialization with boost::asio in one of our software, but we have a critical issue which prevents our further work. It refers to the "Back Versioning" known problem in TODO section: "It has been suggested that a useful feature of the library would be the ability to create "older versions" of archives. Currently, the library permits one to make programs that are guaranteed the ability to load archives with classes of a previous version. But there is no way to save classes in accordance with a previous version. At first I dismissed this as a huge project with small demand. A cursory examination of the code revealed that this would not be very difficult. It would require some small changes in code and some additional tests. Also it would require special treatment in the documentation - perhaps a case study. " *We want to ask what is status of this issue and can we expect to fix this in near future.* This is a networking project, our program compiled with e.g. boost 1.62 or some future version must create archives that can be (sent over the network and then) read on the program compiled with older version like 1.57 for example (as now available by default of Windows/cygwin). We would hope that we can do something like; Archive ar; ar.set_compatibility_boost_version(1, 55); ar << ... We would also need to backport the patch to older version of boost archive, so they also can write archives readable by (even older) versions. In the end we expect to run machines with: boost 1.55 (plus patch to set compatibility) boost 1.57 (plus patch to set compatibility) boost 1.58 (plus patch to set compatibility) boost 1.62 (perhaps by default with the set compatibility option) and each of this computers needs to write archive readable by all other versions (set they would all set compatibility to lowest common version). Without this functionality we can not use boost archive in this project. We would like to help you test/backport this fix and perhaps even try to code it, although we do not yet have any experience in writing code for boost library itself. Can we expect this functionality to be written in e.g. this year? Best regards

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[doc] Liven up Boost Documentation with Java Script?
by Krzysztof Jusiak 01 Mar '16

01 Mar '16

Dear Boosters, I'm writing to ask about your opinion regarding more interactive documentation for Boost. I know already that some of you would like to see online documentation without Java Script and that's absolutely fine and I agree that documentation should be available for anyone and any configuration. Nevertheless, I would like to know what the Boost community thinks about having following features in the documentation... * Run the code online (allows to check library with one click) * Comments (allows commenting on the documentation) * Chats (allows discussing issues and solutions) Personally, I have found above features extremely useful when checking out other languages/libraries and therefore I have implemented solutions for C++ too. Please, check it out (JS is required)... http://boost-experimental.github.io/msm-lite http://boost-experimental.github.io/di If there is an interest I can provide generic solution to allow developers to write documentation using markdown (mkdocs) and simply integrate it with their libraries. Currently, theme is just slightly modified version of readthedocs, however Paul Fultz II has prepared a boost theme for Fit library ( https://github.com/pfultz2/mkdocs-boost) already and it might be easily integration with the JS facilities provided. Cheers, Kris

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[ublas]Contribute about Toeplitz Matrix
by Shangtong Zhang 01 Mar '16

01 Mar '16

Hi David Bellot, It’s disappointed that boost was rejected by gsoc 2016. I was interested in ublas project, and have implemented parts of toeplitz matrix. Anyway I don’t want to abandon my implementation half way, so I’d like to continue on toeplitz matrix. Would you like to guide me to succeed in integrating toeplitz matrix into ublas? Thanks, Shangtong Zhang, Senior Student, School of Computer Science, Fudan University, PRC.

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