August 2014 - Boost - lists.preview.boost.org

[GSoC] [Boost.Hana] Formal review request
by Louis Dionne 21 Sep '14

21 Sep '14

Dear Boost, It has been a while since I've given news about my GSoC project, Boost.Hana[1]. Things are going very well and I uploaded the library to the Boost Incubator. I think it is time to push the library forward for review. As the author, I know everything that's left to be done and polished before I can be fully satisfied. Still, I believe the library is worthwhile in its current state as it implements a superset of the functionality found in the Boost.MPL and Boost.Fusion. I also think the library will benefit greatly from a larger user base and more feedback. Here are some caveats: - The library requires a full C++14 compiler, so only Clang 3.5 can compile the unit tests right now. However, compilers will eventually catch up. Also, pushing cutting edge libraries forward might motivate compilers to support C++14 ASAP, which is probably a good thing. - The library is not fully stable yet, so interface changes are to be expected. I don't see this as a problem as long as this is documented, especially since I expect Hana to be used mostly for toying around for at least a while. I could be mistaken. So unless someone thinks the library isn't ready or would get rejected right away in its current state for reason X, I am requesting a formal review for Boost.Hana. Regards, Louis [1]: http://github.com/ldionne/hana

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[mpl] Modularization pull request
by Andrey Semashev 17 Sep '14

17 Sep '14

Hi, I've created this pull request: https://github.com/boostorg/mpl/pull/11 to separate core components of Boost.MPL to a sub-library. The intent of this pull request is to reduce dependencies added by MPL to its dependent libraries, when only the basic MPL components are required. In particular, it should help resolving circular dependency between MPL and TypeTraits. Please, have a look at the list of moved components and let me know if you have any comments.

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[core/noncopyable][test/boost::unit_test::singleton] massive test failures
by Joaquin M Lopez Munoz 11 Sep '14

11 Sep '14

Hi, There's a problem with noncopyable and boost::unit_test::singleton in Intel 13 for Linux in C++11 compatibility mode that's rippling through many Boost libs. To list a few: date_time: http://tinyurl.com/lkeakab geometry: http://tinyurl.com/n3rajyn regex: http://tinyurl.com/kxkqo4c tuple: http://tinyurl.com/oz3vlct The error messages go like protected function "boost::noncopyable_::noncopyable::noncopyable()" [...] is not accessible through a "boost::noncopyable_::noncopyable" pointer or object[...] protected function "boost::unit_test::singleton<Derived>::singleton()" [...] is not accessible through a "boost::unit_test::singleton<boost::unit_test::unit_test_log_t>" pointer or object[...] which are manifestations of the following compiler bug: https://software.intel.com/en-us/forums/topic/404755 The report also indicates a simple workaround consisting of replacing BOOST_CONSTEXPR noncopyable() = default; with noncopyable() {} (seemingly, this would also fix boost::unit_test::singleton automatically.) Maybe the maintainer of boost:noncopyable can try a fix for ICC 13 along these lines? This can potentially clear a ton of yellow cells. I'd volunteer a pull request but alas I don't have local access to that compiler. Thank you, Joaquín M López Muñoz Telefónica

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NTCTS Iterator [was: Interest in is_iterator type trait?]
by Beman Dawes 08 Sep '14

08 Sep '14

On Tue, Aug 19, 2014 at 1:56 PM, Peter Dimov <lists(a)pdimov.com> wrote: > Beman Dawes wrote: > > Source can be a iterator to a NTCTS or a container. >> > > An iterator to an NTCTS? That's an interesting invention. :-) > See http://beman.github.io/ntcts_iterator/ or https://github.com/Beman/ntcts_iterator --Beman

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sqlpp11, 3rd iteration
by Roland Bock 04 Sep '14

04 Sep '14

Dear Boosters, Quite a bit has happened since last I reported about sqlpp11 in this forum [1,2]. I have incorporated a lot of the feedback you gave me, hopefully bringing the library closer to a reviewable state. Source: https://github.com/rbock/sqlpp11 Doku: https://github.com/rbock/sqlpp11/wiki (not at all formal yet) I am hoping for more feedback both here and live at CppCon (http://sched.co/1r4lue3) Here are some noteworthy changes: _Restructuring:_ The code has undergone a major restructuring, leading to a much simpler and thereby much more flexible way to define the structure of SQL statements. As a result, it would now be quite simple to add vendor specific features sqlpp11 connector libraries. Dominique Devienne mentioned array binding for inserts, Johan Baltié mentioned hierarchical searches (both features of Oracle). If you are interested in writing a connector and adding such features, please let me know, I'll walk you through it. _NULL handling:_ Enabled by the restructured code and spurred by the library quince by Michael Shepanski, sqlpp11 can now calculate which result fields can or cannot be NULL. Speaking of which, handling NULL for result values has been discussed a lot. The library now has compile-time configurable behavior, you can choose between an std::optional-like interface and mapping NULL to the trivial value of the result type, e.g. 0 for numbers or "" for strings, see also https://github.com/rbock/sqlpp11/wiki/NULL _Connectors:_ Matthijs wrote a new postgresql connector from scratch, see https://github.com/matthijs/sqlpp11-connector-postgresql The sqlite3 connector received a bunch of corrections, thanks to dirkvdb _Compilers:_ Known to compile with clang>=3.1 and gcc>=4.8. I currently cannot test with MSVC or Intel or others, but if you happen to have the latest top notch version of any of those, I'd be interested in what they have to say about sqlpp11. Cheers, Roland [1]: http://lists.boost.org/Archives/boost/2013/11/208388.php [2]: http://lists.boost.org/Archives/boost/2014/02/211206.php

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[move][unique_ptr] c++14 unique_ptr comes to town
by Ion Gaztañaga 03 Sep '14

03 Sep '14

Hi to all, We've discussed about a boostified version of std::unique_ptr several times in later years. I decided we could not continue with this hole in the Boost toolset and implemented in Boost.Move a unique_ptr that follows the C++14 interface. Commit here: SHA-1: e1da7c5ca1162841f643331af891a9a730eba118 http://github.com/boostorg/move/commit/e1da7c5ca1162841f643331af891a9a730eb… This implementation is also usable from C++03, and apart from the general limitations of the Boost.Move machinery, it should be really uesful for C++03 users. I would like to make this implementation the official boost::unique_ptr implementation, but until the community approves this, it's in boost::movelib namespace (boost::move it's a function so I needed to tweak the namespace name). I would like to thank Howard Hinnant for his great public implementation of the emulated unique_ptr published here: http://home.roadrunner.com/~hinnant/unique_ptr03.html I've ported and refactored Howard's extensive testsuite to implement boost test cases. Really useful to detect many implementation errors and details. I've found unique_ptr much harder to write than I expected. The standard text is really detailed and helps implementors, but things like allowed conversion between pointers and deleters and several ICEs and different SFINAE parties on many compilers made the work quite entertaining. The API is taken from the draft n3797 and the implementation has some differences with the standard. The main reason for this is that I wanted to make unique_ptr as lightweight as possible avoiding external dependencies, as it's interesting to implement idioms like PIMPL. Main attributes and differences with the standard: -> Implemented in two headers: <boost/move/unique_ptr.hpp> and <boost/move/make unique.hpp>. -> <boost/move/unique_ptr.hpp>: Boost.Move is the only heavyweight dependency. Not even that, as unique_ptr.hpp only uses boost/move/utility_core.hpp, that does not depend on any external library excepct BoostConfig and StaticAssert. No TypeTraits, MPL and others. Only Boost.Config, BOOST_STATIC_ASSERT and BOOST_ASSERT are used in the implementation. No standard library headers used (no pointer_traits, memory or other utilities). -> <boost/move/make unique.hpp>: Boost.PP is used in compilers without variadic templates. This is the main reason to have a separate make_unique.hpp header and avoid pulling Boost.PP for c++03 users that only want to have C++11 unique_ptr. -> unique_ptr's "operator <" is implemented as x.get() < y.get() instead of std::less<CT>(). std::less requires <funcional>. std::common_type requires C++11 standard library or some partial emulation based on Boost.TypeOf. I don't think 99,99% of users will notice the difference. For raw pointers, in all our platforms comparisons provide strict weak ordering. If a smart pointer writer specializes std::less for its smart pointer, it should be a law against that. -> It's assignable from literal 0. I found some problems in some compilers trying to write a constructor for that. -> nullptr support is conditional on !defined(BOOST_NO_CXX11_NULLPTR) but I think really should have a Boost nullptr for C++03 compilers. Let's put Meyer's nullptr (http://en.wikibooks.org/wiki/More_C%2B%2B_Idioms/nullptr) in Boost for BOOST_NO_CXX11_NULLPTR compilers. -> unique_ptr<T[]> is convertible to other types when conversion is considered safe. This means that unique_ptr<T[]> is convertible to unique_ptr<const volatile T[]>. Conversion from T[] to U[] is considered safe if remove_cv<T> is the same type as remove_cv<U> and unique_ptr<T[]>::pointer is convertible to unique_ptr<U[]>::pointer. This is a feature that might go to C++17 (http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#2118) Safe conversions in reset() and constructors from pointers are also implemented in unique_ptr<T[]>. I tested the implementation in GCC{4.4, 4.6, 4.7, 4.8} Clang3.4 and MSVC{7.1, 8.0, 9.0, 10.0, 11.0, 12.0} in 32/64 bits, debug/release and C++03/C++11 modes (where applicable). The class documentation is generated with Boost.Move documentation and the most part of it is taken from the standard. I haven't added a tutorial to Boost.Move but I plan to it based on Howard's c++03 unique_ptr tutorial. I hope you find this addition to Boost.Move useful. If you think the implementation is good enough to be the official boost::unique_ptr implementation living in Boost.SmartPtr, porting should be easy, except for the documentation part. That would require either combining somehow handwritten and Quickbook produced documentation or writing new docs for unique_ptr. Best, Ion

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Checking interest in DynamicLoad/DLL/DSO/Plugin library
by Antony Polukhin 02 Sep '14

02 Sep '14

Hi, There is a basic implementation of a header only Plugin library: https://github.com/apolukhin/Boost.Plugin Documentation with examples could be found here: http://apolukhin.github.io/Boost.Plugin/index.html Is there an interest in such library in Boost community? What features are missing in the library? Looking forward to hearing from you. Any feedback is more than welcomed. -- Best regards, Antony Polukhin

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Review Wizard Status Report for August 2014
by Ron Garcia 02 Sep '14

02 Sep '14

============================================== Review Wizard Status Report for August 2014 ============================================== News ==== 1. Fiber Accepted Provisionally. January 2014. 2. Align Accepted. April 2014. 3. TypeIndex Accepted. May 2014. 4. Convert Accepted. June 2014. 5. Boost 1.56 Released -- New Libraries: Align, TypeIndex Open Issues =========== The following libraries have review managers, but have not yet been scheduled for review: * Range Extensions - added May 2012; review manager: Neil Groves. The following libraries have been accepted to Boost, but have not yet been integrated into Boost Git: * Contract - accepted September 2012; author: Lorenzo Caminiti. The following libraries have been accepted and submitted to Boost Git, but have not yet appeared in a release: * Convert - accepted June 2014; author: Vladimir Batov. The following libraries have been accepted provisionally to Boost, but have not been submitted for mini-review and full acceptance: * Fiber - accepted provisionally January 2014; author Oliver Kowalke. General Announcements ===================== As always, we need experienced review managers. Please take a look at the list of libraries in need of managers and check out their descriptions. In general review managers are active boost participants, including library contributors, infrastructure contributors, and other mailing list participants with a substantial track record of constructive participation. If you can serve as review manager for any of them, email Ron Garcia or John Phillips, "rxg at cs dot ubc dot ca" and "johnphillipsithica at gmail dot com" respectively. We are also suffering from a lack of reviewers. While we all understand time pressures and the need to complete paying work, the strength of Boost is based on the detailed and informed reviews submitted by you. If you are interested in reviewing a library but won't have time during the review period, you can always prepare your review ahead of time. No rule says you can only work on a review during the review period. A link to this report will be posted to www.boost.org. If you would like us to make any modifications or additions to this report, please email Ron or John. The review schedule is an unordered list of the libraries awaiting review. As such, any library on the schedule can be reviewed once the developer is ready, a review manager has been secured, and the manager, developer, and wizards agree on a date to schedule the review. Review Schedule =============== * Join (M) * Sorting (M) * Quaternions, Vectors, Matrices (M) * Block Pointer (M) * Singularity (M) * Extended Complex Numbers (M) * Metaparse (M) * Boost.Range Extensions * Nowide (M) * Array (M) * STL Extensions (M) * Countertree (M) * Process (M) * Asynchronous File I/O (M) * Application (M) * Edit Distance (M) * Mixin (M) ``(M)`` marks libraries that need review managers. -------------------- Join ---- :Author: Yigong Liu :Review Manager: Needed :Download: http://channel.sourceforge.net/ :Description: Join is an asynchronous, message based C++ concurrency library based on join calculus. It is applicable both to multi-threaded applications and to the orchestration of asynchronous, event-based applications. It follows Comega's design and implementation and builds with Boost facilities. It provides a high level concurrency API with asynchronous methods, synchronous methods, and chords which are "join-patterns" defining the synchronization, asynchrony, and concurrency. Sorting ------- :Author: Steven Ross :Review Manager: Needed :Download: https://github.com/boost-vault/Sorting :Description: A grouping of 3 templated hybrid radix/comparison-based sorting algorithms that provide superior worst-case and average-case performance to std::sort: integer_sort, which sorts fixed-size data types that support a rightshift (default of >>) and a comparison (default of <) operator. float_sort, which sorts standard floating-point numbers by safely casting them to integers. string_sort, which sorts variable-length data types, and is optimized for 8-bit character strings. All 3 algorithms have O(n(k/s + s)) runtime where k is the number of bits in the data type and s is a constant, and limited memory overhead (in the kB for realistic inputs). In testing, integer_sort varies from 35% faster to 2X as fast as std::sort, depending on processor, compiler optimizations, and data distribution. float_sort is roughly 70% faster than std::sort. string_sort is roughly 2X as fast as std::sort. Quaternions, Vectors, Matrices ------------------------------ :Author: Emil Dotchevski :Review Manager: Needed :Download: http://www.revergestudios.com/boost-qvm/ :Description: QVM defines a set of generic functions and operator overloads for working with quaternions, vectors and matrices of static size. The library also defines vector and matrix data types, however it allows users to introduce their own types by specializing the q_traits, v_traits and m_traits templates. Block Pointer ------------- :Author: Phil Bouchard :Review Manager: Needed :Download: https://svn.boost.org/svn/boost/sandbox/block_ptr/ :Description: Deterministic memory manager of constant complexity capable of handling cyclic collections. Singularity ----------- :Author: Ben Robinson :Review Manager: Needed :Download: https://github.com/cppmaven/Singularity :Description: The Singularity Design Pattern allows you to restrict any class to a single instance. Unlike the infamous Singleton, Singularity gives you direct control over the lifetime of the object, does not require you to grant global access to the object, nor does it limit you to the default constructor for that object. Extended Complex Numbers ------------------------ :Author: Matthieu Schaller :Review Manager: Needed :Download: http://code.google.com/p/cpp-imaginary-numbers/ :Description: The library is an extension of the std::complex class addressing two issues: 1. The standard does not guaranty the behaviour of the complex class if instantiated with types other than float/double/long double. 2. Some calculation where pure imaginary numbers (i.e. multiples of sqrt(-1)) appear are unnecessarily slowed down due to the lack of support for these numbers. The code I submit contains two interleaved classes boost::complex and boost::imaginary which can be instantiated with any type T provided T overloads the usual arithmetic operators and some basic (real) mathematical functions depending on which complex function will be used. It is thus an extended version of Thorsten Ottosen's n1869 proposal (http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2005/n1869.html) Metaparse --------- :Author: Abel Sinkovics :Review Manager: Needed :Download: http://abel.web.elte.hu/metaparse/metaparse.zip :Description: Metaparse is a library for constructing parsers parsing at compile-time based on template metaprogramming. The parsers built with the library take boost::mpl::strings as input and can produce - types - objects (types with public static members) - callable C++ functions (types with public static method) - template metafunction classes as output (based on the input being parsed). On compilers supporting constexpr the library provides the following syntactic sugar for writing the input of the parsers: BOOST_STRING("this is a string") The library can be used for implementing DSLs in C++, including DSLs making C++ template metaprogramming easier (see examples). Range Extensions ---------------- :Author: Akira Takahashi :Review Manager: Neil Groves :Download: https://github.com/faithandbrave/OvenToBoost :Description: This project adds some features of the Oven Range Library to Boost.Range. Features: - Additional Range Adaptors (taken, taken_while, dropped, dropped_while, elements, elements_key, memoized, outdirected) - Extensions for using Lambda (regular function, regular operator) - Infinite Range (iteration function) - and additional range utilities. Nowide ------ :Author: Artyom Beilis :Review Manager: Needed :Download: http://cppcms.com/files/nowide/ :Description: This library makes cross platform Unicode aware programming easier. It provides an implementation of standard C and C++ library functions, such that their inputs are UTF-8 aware on Windows without requiring to use Wide API. Array ----- :Author: Brian Smith :Review Manager: Needed :Download: https://github.com/BrianJSmith/Array :Description: The array class is a C++11 compatible implementation of static multidimensional arrays. STL Extensions -------------- :Author: Vadim Stadnik :Review Manager: Needed :Download: https://github.com/vstadnik/stl_ext_adv_review :Description: The proposed library [stl_ext_adv] offers augmented array based B+ trees and STL containers that support the interfaces of the C++03 sequences and associative containers. The library offers a number of extensions and performance improvements that are not available in C++03 and C++11 standard containers. Countertree ----------- :Author: Francisco Jose Tapia :Review Manager: Needed :Download: https://dl.dropbox.com/u/8437476/works/countertree_code_doc.zip :Description: This library is an implementation of a binary red-black counter tree. This tree have an additional counter in each leaf. This permit the access to the elements by the position, like in a vector. It is a random access container with random access iterators. COUNTERTREE This kind of trees have an additional counter in each leaf. This permit the access to the elements by the position, like in a vector. It is a random access container with random access iterators. With unordered information we have a vector with the same speed inserting and deleting in any position (O(log N)). With ordered information, we have the classes set, multiset, map and multimap, with identical interface than the STL classes, with the plus of access to the elements by position, like in a vector. The iterators are random access , and you can subtract them. SUBALLOCATOR The suballocator is a layer between the allocator and the data structures, compatible with any allocator with the STL definition. The suballocator replace to the allocator in the allocation of equal size elements. It provides speed, return the unused memory and decrease the memory used by the program and improve the cache performance due to the data locality improvement ( 30% of improvement of speed respect the std::allocator with GCC 4.7) Process ------- :Author: Boris Schaeling :Review Manager: Needed :Download: http://www.highscore.de/boost/process0.5/process.zip :Description: Boost.Process is a library to manage system processes. It can be used to: * create child processes * setup streams for child processes * communicate with child processes through streams (synchronously or asynchronously) * wait for processes to exit (synchronously or asynchronously) * terminate processes Asynchronous File I/O --------------------- :Author: Niall Douglas and Paul Kirth :Review Manager: Needed :Download: https://github.com/BoostGSoC/boost.afio/archive/boost-peer-review.tar.gz :Description: Boost.AFIO is a linear scalable, batch, chainable, asynchronous closure execution engine with an almost wait free implementation extending Boost.ASIO and Boost.Thread specialised as a portable asynchronous file i/o implementation library. Implementation of this first version has been kept as simple as possible (~ 1000 active LOC) at the cost of some performance, though with a good compiler you can expect 25-50% of the performance of using raw Boost.ASIO. Application ----------- :Author: Renato Tegon Forti :Review Manager: Needed :Download: https://github.com/retf/Boost.Application :Documentation: http://www.dokfile.com/appbeta4/docs/libs/application/doc/html/index.html :Description: Application provides an application environment, or start point to any people that want a basic infrastructure to build an system application on Windows or Unix Variants (e.g. Linux, MacOS). Application uses behaviours modeled using 'aspects' concept proposed by 'Vicente J. Botet Escriba', that allow easy extension and customization of library components. The application modes uses these components internally to achieve the user desirable behaviours. Application provide many useful ready-to-use features, e.g: * Run application as Windows Service; * Run application as UNIX/POSIX Daemon; * Plugin extension system; * Process(executable) Single instance Instantiation support; * Application SIGNAL/Callbacks customization; * Windows Service Setup feature; * And many others. Edit Distance ------------- :Author: Erik Erlandson :Review Manager: Needed :Download: https://github.com/erikerlandson/algorithm/tree/edit_distance/sequence :Description: The edit distance is the length of the shortest (or least-cost) edit script from one sequence to another, where an edit script is defined as a sequence of insertion, deletion and (optionally) substitution operations. The function implementing the edit distance is named edit_distance. This function will return the edit distance between two sequences, where sequences may be any valid range object supporting forward iteration. The edit_distance function will also, if requested, return the edit script. Mixin ----- :Author: Borislav Stanimirov :Download: https://github.com/iboB/boost.mixin :Documentation: http://ibob.github.io/boost.mixin/ :Review Manager: Needed :Description: Boost.Mixin is a library that allows the composition and modifications of polymorphic types at run time. Types and objects are constructed out of building blocks called mixins. The library uses the type boost::mixin::object as a placeholder, whose instances can be extended with existing classes (mixins), thus providing a particular instance with the functionality of all those types. Accessing the newly formed type's interface is made through messages: stand-alone functions generated by the library, which can be thought of as methods. This is given while also having full abstraction between the interface and the definition of types. An existing feature in another language similar to Boost.Mixin and also an inspiration for the library are the mixins in Ruby. The library also has similarities with the pattern entity-component-system. Libraries under development =========================== See http://svn.boost.org/trac/boost/wiki/LibrariesUnderConstruction for a current listing of libraries under development.

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[build] b2 headers don't work for sublibs
by Andrey Semashev 01 Sep '14

01 Sep '14

Hi, I'm trying to move some headers of Boost.MPL to a sublib Boost.MPL.Core. I've reorganized the repository as follows: libs mpl book core include boost <- here and below are core headers test index.html doc example include boost <- here and below are the rest headers meta preprocessed test .git .gitattributes README.md index.html sublibs The problem is when I run 'b2 headers' the command creates a symlink boost/mpl pointing to libs/mpl/include/boost/mpl, which leaves out all headers from libs/mpl/core/include/boost/mpl. How do I instruct Boost.Build to create links to the core headers?

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Re: [boost] [graph] strong_components & depth_first_visit feature proposal
by Jeremiah Willcock 31 Aug '14

31 Aug '14

On Wed, Aug 27, 2014 2:39 AM EDT Alexander Lauser wrote: >> * Another minor question: Why are not all events of a >> DFS-visitor optional (like finish_edge is)? I think this would make >> implementing a partial DFS-visitors easier (by not having to derive from >> dfs_visitor in order to provide events that one is not interested in). >> >> Have you tried deriving from default_dfs_visitor? > >Yes, but why only make finish_edge optional? I think it would make >user-code (slightly) clearer if all events were optional. It's no big >deal, of course, and that's why it's a minor question. > >Alex > > >PS: For the background, I'm quite new to Boost and for me it is somewhat >arbitrary that everything is mandatory but finish_edge. The reason, >however, seems to be historical: I recently saw that, at least in Boost >version <= 1.39, there was no finish_edge-event. That is why it is (or at least is trying to be) optional. Visitors from before that event was added would become incorrect if it was not optional, leading to compatibility problems. Making all of the events optional would be possible as long as Boost.TTI could detect all of the signatures that are in use for them currently. -- Jeremiah Willcock

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