March 2015 - Boost - lists.preview.boost.org

release1.58 -- Permission to merge Boost.Optional
by Andrzej Krzemienski 12 Mar '15

12 Mar '15

Hi, I have three bug fixes in Boost.Optional on branch develop waiting to be merged to master. Apparently I missed the deadline for the Beta release. Is there any chance I can still put them into 1.58 release? Can I merge the bug fixes to master? Regards, &rzej

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[GSoC '15] Boost Documant Library development
by Abhinav Tripathi 12 Mar '15

12 Mar '15

Hi, I am 2nd year B.Tech Student in IIT Indore,India. I have pretty much experience (approx 7 years) with C++ and many of its libraries... I am interested in development of the Document Library for Boost. I have a rough idea on what exactly is required in the project and am quite interested in doing this one. I was looking for any suggestions/comments to help me get going in this direction. . Regards, Abhinav

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Re: [boost] [Boost-maint] [context, config] Always setting address-model and architecture (Was: Conflicts when building libraries at root)
by Vladimir Prus 11 Mar '15

11 Mar '15

On 02/18/2015 05:55 PM, Jürgen Hunold wrote: > Hi Volodya, > > Am Mittwoch, 18. Februar 2015, 14:28:48 schrieb Vladimir Prus: >> On 01/05/2015 10:37 PM, Jürgen Hunold wrote: >>> >>> Unfortunately, we still have Boost.Context open. >> >> Okay, so the problem we're facing is that building master results in: >> >> error: Tried to build the target twice, with property sets having >> error: these incompatible properties: >> error: >> error: - none >> error: - <address-model>32 <architecture>x86 >> >> What happens is this: >> >> - Context library is built >> - It detects default address model and architecture of the current >> toolchain, and adds those to requirements >> - Since there's a global dependency on 'headers' target, this pretty much >> immediately rebuilds everything with new address-model and architecture >> properties. > > Not correct: Boost.Context needs Boost.System so it requires a build with > those properties. As they have currently have no defaults, the explicit values > differ from the implizit default (none) for both. Well, it my brief check, it was the headers->system path that first requested system with address-model=32. Anyway, it does not matter for the rest of this discussion. >> - We get property set clash > > Correct. > >> One way to solve this is to restructure Boost.Context setup so that added >> properties do not escape. It's doable, but probably will be fragile. > > No doubt. > >> Another way is to take libs/context/config, move it to libs/config, and make >> sure these properties are applied globally. That seems preferable. John, >> any objections? > > I thought the correct way would be to move the architecture detection upwards? That's roughly what I propose, too - but there are few further tweaks and options. > We would need something along those lines (from context/bulld/Jamfile.v2) > > alias select_asm_context_sources > : asm_context_sources > : [ architecture.architecture ] > [ architecture.address-model ] > ; > > in boostcpp.jam in order to detect the architecture everywhere. It would then > be helpfull to have sensible default values in order to shorten the generated > paths for those defaults. Right, so steps would be: 1. Move actual tests into config (we do need to have a few cpp files) 2. Move architecture.jam into either Boost.Build or boostcpp.jam 3. Make sure we don't generate extra path elements for default address model 4. Introduce a way to do these tests without requiring a bunch of .cpp files - sure Boost.Build can generate them on the fly. 5. Make these checks be automatic for all projects. It seems that 1-2 should solve the immediate problem, and 1-3 should be pretty good, although going all the way to 5 would be cool. > Another solution would be to generate a "header-only" variant of Boost.System > and use this nearly everywhere. This would solve *lots* of dependency > problems... Not sure I have an opinion on that. -- Vladimir Prus CodeSourcery / Mentor Embedded http://www.mentor.com/embedded-software/

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[svg] is there any interest in a Scalable Vector Graphics library?
by Oleg Maximenko 11 Mar '15

11 Mar '15

Hi, I developed library that carries out large amount of tasks related to SVG reading - parses various SVG syntaxes (with Spirit), makes some conversions and implements few non-trivial algorithms common to SVG reading applications. Using this library developer may focus on importing/drawing tasks, leaving SVG details to library. I believe that it is (almost) generic enough for Boost standards, but not sure if there is a place for it in Boost collection. Should I move toward library proposal? Any feedback is welcome. http://svgpp.org/ https://github.com/svgpp/svgpp Thanks, Oleg

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Mailing List For GSoC 2015
by Abhinav Tripathi 11 Mar '15

11 Mar '15

On the site, it was just written to discuss the projects in mailing lists. Wanted to confirm if it the correct list to discuss about GSoC 2015 Projects. . If it is not please let me know the correct one. . Thanks and regards, Abhinav

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[type_erasure] Downcasting is now possible
by Steven Watanabe 10 Mar '15

10 Mar '15

AMDG I've been asked about a function for downcasting an any several times, and I finally implemented it. Short story: you can now use dynamic_any_cast to convert between two arbitrary any types. Here's a quick example which tries to cast a boost::any equivalent to a boost::function equivalent. using plain_any = any<mpl::vector< copy_constructible<>, relaxed> >; template<class Sig> using any_function = any<mpl::vector< callable<Sig>, copy_constructible<>, relaxed> >; bool try_call(const plain_any& arg) { try { auto fun = dynamic_any_cast<any_function<void()> >(arg); fun(); } catch(bad_any_cast&) { return false; } return true; } void global_register() { register_binding<copy_constructible<>, void(*)()>(); register_binding<typeid_<>, void(*)()>(); register_binding<callable<void()>, void(*)()>(); } void do_something() { std::cout << 42 << std::endl; } int main() { global_register(); plain_any x = &do_something; if(try_call(x)) { std::cout << "x is a function" << std::endl; } plain_any y = 10; if(!try_call(y)) { std::cout << "y is NOT a function" << std::endl; } } The calls to register_binding are necessary for this to work, unfortunately. I don't think it's possible to implement dynamic_any_cast without some kind of registration, but at least it only needs to be called once for each concept/type combination. If anyone has any better ideas about how to handle this, I'd love to hear it. Comments, questions, and criticism are welcome. In Christ, Steven Watanabe

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Boost GSoC '15. Enchanced Vector and Deque Containers
by Pranav Vaish 10 Mar '15

10 Mar '15

Hello developers, My name is Pranav Vaish. I'm a second year Undergraduate in Computer Science at Indian Institute of Technology, Kanpur. I am extremely interested in doing a GSoC project on Enhanced Vector and Deque Containers. I have used std::vector and std::deque containers (Default C++ containers. Not C++11 ones) several times and am quite familiar with their usages, though not so much with their code . I am strong at programming in C++ but have never written any library code prior to this. I am competent at understanding and working with all algorithms necessary for this project. I have spent some time thinking about the problem for the competency test and I would like know if I am supposed to understand the code of the standard containers and modify the code to suit our purposes or to rewrite it all from scratch in my own way. Also must I have any knowledge about BOOST code? If yes, which part of it? Thank You, ------ Pranav Vaish

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[random][rational] Is there any standard way to generate a random rationals?
by Damian Vicino 10 Mar '15

10 Mar '15

Hi, I’m using Boost.Rational in a simulation program. for some experiment, I want to generate some random values between 2 rational numbers. I’m wondering if someone already worked on this.

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gSoC 2015 - Boost Document Library development Project
by Anurag Ghosh 10 Mar '15

10 Mar '15

Hello I'm Anurag Ghosh, a Computer Science student in 2nd year. I'm interested in working for Boost in GSoC 2015 and found the Boost Document Library development project really interesting. I'm reading the links provided on the page. Any pointers on how should I go about ahead after that ? Thanks Anurag Ghosh

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GSoC 2015 - Boost.uBLAS a library for matrix computations Project
by Yan Ni 10 Mar '15

10 Mar '15

Hello I'm Yan Ni, a CS undergraduate student in 4th year. I am interested in working for Boost in GSoC 2015 and found the uBLAS project very interesting. I've read some the codes on github and has written a little code (including a simple test) of Gaussian Elimination Algorithm as the competency test: https://github.com/leckie-chn/ublas. I've also read about Raj's post about the algorithms need to be implemented. And I think that the focus on this project are both accuracy (using some numerical algorithm instead of classical math methods)and speed (regarding cache & memory utilization). Please let me know your preference. Thank you. -- with kind regards ------------------------------------------------------------------ Yan Ni, undergraduate of Department of Computer Science, School of Electronic Engineering & Computer Science, Peking University

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