November 2013 - Boost - lists.preview.boost.org

Data Structure and Algorithms yet to be inplemented
by Manmohit Rekhi 11 Nov '13

11 Nov '13

Hi, I would really be grateful if could get to know 1)which Data Structures and Algorithms are yet to be implemented? 2)How can i get started on them? 3)Are there any constraints on the libraries i can use to implement them? Thanking you Manmohit Rekhi

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[UUID] Document typo
by Naked Short-Selling 11 Nov '13

11 Nov '13

http://www.boost.org/doc/libs/1_55_0/libs/uuid/uuid.html#Nil I believe is_null() really meant "is_nil()" here...

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[git][ Last merge before git conversion.
by Vicente J. Botet Escriba 10 Nov '13

10 Nov '13

Hi, I would like to know if there will be some time (~1 week) to merge the new features and bug fixed in the release branch before svn is closed for git migration. Note that the provisional calendar was: 8 November : release 1.55 15 November: Provisional: Close subversion for git conversion. Best, Vicente

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[intrusive] possible workaround for vc12 compile errors
by Daniela Engert 10 Nov '13

10 Nov '13

Hi, I've attached a patch to ticket #9332 "has_member_function_callable_with.hpp compile error on msvc-12.0" (https://svn.boost.org/trac/boost/ticket/9332) This patch seems to fix the problem. My far-from-perfect understanding of C++ seems to indicate, that the root cause is in line 201: template< class F , std::size_t N = sizeof((boost::move_detail::declval<F>(). BOOST_INTRUSIVE_HAS_MEMBER_FUNCTION_CALLABLE_WITH_FUNCNAME (), 0))> struct BOOST_PP_CAT(zeroarg_checker_, BOOST_INTRUSIVE_HAS_MEMBER_FUNCTION_CALLABLE_WITH_FUNCNAME) the sizeof expression is evaluated with an unknown type U in declval<U>(). Ciao Dani

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Re: [boost] sqlpp11: SQL for C++
by Roland Bock 10 Nov '13

10 Nov '13

On 2013-11-10 15:58, niXman wrote: > Roland Bock 2013-11-10 12:15: > >> No, sqlpp11 itself only depends on a decent C++11 compiler and matching >> STL. > > I think I can write a code generator using boost.preprocessor. But I > need the documentation of DDL, of course. > I was talking about SQL's DDL (http://en.wikipedia.org/wiki/Data_definition_language) Unfortunately every vendor seems to be using some additions, so that the task is not too simple in all generality, I guess... But using the preprocessor to generate the table types could be a very nice tool in some cases. For instance if you are using in-memory databases with Sqlite3. As a trivial byproduct it could also produce the create table string, so that I would not have to maintain that in two places. Also for such a purpose, it would make sense to restrict the DDL to a common subset. With larger tables, I guess I'd stick with my current approach though: running a separate code-generator as part of the build process. The main benefit is that I get clearer error message pointing to C++ code that exists outside the compiler memory in case the code generator produces incorrect output or I use the generated code in the wrong way, etc. Another benefit of using external code generators is string handling. In our company we use CamelCase for classes, camelCase for members and underscore separated compounds for SQL names. An external code generator can easily translate, of course, but the preprocessor is not equipped for string manipulation, afaik. But again, I can imagine a nice usage of a prepocessor-based code generator for in-memory databases with no external representation. Regards, Roland

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[utility] Any interest for a macro which automatically creates default move-semantics, comparisson etc for a class
by Viktor Sehr 10 Nov '13

10 Nov '13

I've created a macro which automatically creates: - move constructor\assignment - swap member function - operator== and operator!= - operator< - assignment operator without side-effects if it throws. Example usage: class Foo { public: Foo() {} DEFAULT_EVERYTHING(Foo, ( (int)(a) ) ( (std::vector<int>)(b) ) ( (float)(c) ) ); }; Any interest, suggestions or ideas? Ofcourse it might be split into several macros depending on what operators the class requests (if it's a move-only class etc), and perhaps an extra parameter enable if a member is up for sorting and comparison. Code available here: https://www.dropbox.com/s/dhkxj94rrh83az0/DefaultEverything.h

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[containers] Are there flat_map/set and stable_vector proposals at work?
by Klaim - Joël Lamotte 09 Nov '13

09 Nov '13

All is in the title: I would like to know if flat_map, flat_set and stable_vector have been proposed for inclusion in the C++ standard library, or if there are works going on to write such a proposal. I find that I use a bit more flat associative containers than tree-based standard associative containers in all my recent projects, and I think that having option in the standard to choose one or the other would be very useful for a lot of devs.

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New Version (0.4) of Boost.Application (Aspect Based) available to comments (RFC).
by Renato Forti 09 Nov '13

09 Nov '13

Hi, I will answer on list too. >> I would like to know if your application class is related only to console applications or is it a generic class that could be implemented also as a gui::application? It is generic. But now we don't provide any specific support to GUI, you can for sample use it with QT, to do this you need use "common mode". >> I'm trying to write a cross platform header only gui library, so I wonder if I should use it (hoping it's a header only library too) or have my own different gui::application class. http://www.dokfile.com/appbeta4/docs/libs/application/doc/html/boost_applica tion/f_a_q_.html#boost_application.f_a_q_.can_i_build_another_application_mo de__what_is_needed_ Well, you can build a application mode that will use your GUI lib, e.g. application::gui use application::common as model. But we have some problem here! 1. Boost.Application is not a boost library yet! (have no support od boost.org) , and it is in working progress status. Things can change! 2. Boost.Application is header only, but have some dependencies that are not header only. http://www.dokfile.com/appbeta4/docs/libs/application/doc/html/boost_applica tion/dependencies.html PS. If you think that this library is interesting to boost, please post on boost.devel, that you have interest on it. http://news.gmane.org/gmane.comp.lib.boost.devel Hope this helps in your decision. If you have any other questions, let me know! -- Renato Forti

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New Version (0.4) of Boost.Application (Aspect Based) available to comments (RFC).
by Renato Forti 09 Nov '13

09 Nov '13

Hi Stas, Thanks for your comments! >> I think it worth noting in documentation that SIGUSR1 is reserved for internal purposes. I will do! >> What do you think about self pipe built-in functionality? It is a widely used trick. I think it can be implemented as an aspect in a quite straightforward way. Can you give more details about what you're proposing here? Elegant signal handler is my main problem in this lib! I want ideas to get it correctly designed! Thanks for documentation appointments, I will fix all! And I forgot to put the main question on message: "Is there any interest in a library like this?" What you think? Thanks a lot!

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[string_ref] string literal constructor
by Michael Marcin 08 Nov '13

08 Nov '13

I noticed string_ref doesn't have a constructor for a string literal. Wouldn't this save a call to strlen for a common case? Ex. template< std::size_t N > basic_string_ref( const charT( &str )[N] ) : basic_string_ref( str, N-1 ) { static_assert(N >= 1, "not a string literal"); } string_ref test( "test" ); I see that adding this directly doesn't work as the compiler is always choosing to decay and pick the const char* overload. Is there no way to make this work?

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