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[Review] The 'Type Traits Introspection' library Review starst next friday, july 1st
by Joel falcou 24 Jun '11

24 Jun '11

According to the schedule, review for the Type Traits Introspection library by Edward Diener will run from friday, July 1st to monday, july 10 2011. =========== What is it? =========== The TTI library, which is an abbreviation for the 'Type Traits Introspection' library, allows a programmer to introspect at compile time the inner elements of a C++ type. The introspection process depends on specifying the name of the inner element by different macros for different types of elements, and then using a generated metafunction to determine whether that element exists within the enclosing type. The inner elements which can be introspected are type, class template, member data, member function, static member data, and static member function. The TTI library is based on the type_traits_ext portion of the Concept Traits Library, with improvements and additions, and also reproduces functionality ( without changing existing code ), for the purposes of completeness, from Boost.MPL regarding introspection of types and templates. The purpose of the library is to provide a consistent set of interfaces for doing compile-time introspection of a type, which other template metaprogrammers can use in their code. If you are at all interested in compile-time introspection of types, please take a look at the functionality of this library. =================== Getting the library =================== The library is available at http://svn.boost.org/svn/boost/sandbox/tti/ Note that this repository will be updated up to next thursday by Edward. =================== Writing a Review =================== The reviews and all comments should be submitted to the developers list, and the email should have "[TTI] Review" at the beginning of the subject line to make sure it's not missed. Please explicitly state in your review whether the library should be accepted. The general review checklist: - 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? And finally, every review should answer this question: - Do you think the library should be accepted as a Boost library? Be sure to say this explicitly so that your other comments don't obscure your overall opinion.

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[1.47.0] Beta 1 Release Notice
by Beman Dawes 21 Jun '11

21 Jun '11

Boost release 1.47.0 beta 1 is now available from SourceForge See http://sourceforge.net/projects/boost/files/ New Libraries: Chrono, Geometry, Phoenix and Ratio. Updated Libraries: Accumulators, Asio, Config, DateTime, Dynamic Bitset, Foreach, Function, Function Types, Graph, Iterator, Lexical Cast, Logic, Math, Meta State Machine, MultiIndex, Proto, Spirit, Tokenizer, Utility, Wave For details of what's in the release, see http://beta.boost.org/users/news/version_1_47_0. Note that the links to files on this web page are for the final release - use the SourceForge link above to get the beta files. There have been reports of build issues with MinGW/CGG and 64-bit Windows/VC++. These are being investigated and hopefully should be cleared up before the final release Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team Beman Dawes Daniel James Eric Niebler Rene Rivera Vladimir Prus

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[boost] [review] [heap] Summary
by Andrew Sutton 18 Jun '11

18 Jun '11

The formal review of Tim Blechmann's Heap library has concluded. Only four votes were cast, although more people commented on issues either on the mailing list or though the Code Collaborator tool. However, from the comments received, the review identified no fundamental problems in the design or implementation of the library that would entail rejection. A such, the Boost.Heap library is ACCEPTED into Boost Votes for the library were cast by: Phil Endecott Daniel Russel Votes against: Thomas Klimpel (provisionally) Andrew Sutton Other comments received during the course of the review were generally positive, with a number of technical issues identified that need to to be addressed. The final version of the library can be fully accepted once Tim has addressed the technical issues identified during the review. Below is a summary of technical concerns. - The pairing heap has a known issue, regarding stack overflows, making it potentially unusable for production code. If the recursion issue can't be adequately solved, then the data structure should carry a much stronger warning label (i.e., put it in an experimental directory). - The performance of b_heap vs. d_ary_heap vs. priority_queue needs to be better characterized. Under what circumstances does one outperform the other. If no convincing scenario can be found where b_heap outperforms the others, then it should also be placed in an experimental directory. - The heap concepts need to be revisited as per comments on the review tool. The concepts should also describe semantics of the operations, not just the interfaces. - There were several comments on the implementation of heap stability. Three alternatives were identified: “naturally stable” heaps (of which no examples were given), the current counter based approach, and a chaining approach. No consensus on the best implementation strategy. Although the counter-based approach is probably adequate for most applications, it is not universally desirable. A more thorough investigation of alternative strategies is encouraged. It would be acceptable to document the investigation in a “Future Work” section of the library documentations (with any experiments also housed in the library). - The notion of Mergeable heaps needs to be better addressed, at least to differentiate between heaps that merge in O(n) or slower time and those that can merge in O(lg n) time. The proposed solution is to write merge as a general heap algorithm and specialize it for Mergeable heaps by calling the member function merge. Also, merge should be destructive, so merge and clear should not be needed. - The documentation must be substantially improved with respect to the overall design of heap data structures (i.e., concepts), especially mutable heaps and best practices. It also needs to provide both theoretical and performance comparisons for the different heaps. - Include documentation of the benchmarking tool in the documentation. It could be instructive for users to evaluate different heap implementations on their host or target architectures. - Document the complexity of == and < for heaps. - Address the comments and issues in the Review Tool. There were other recommendations that should be considered in the long term for the library. - Thorsten Ottosen suggest making b_heap and d_ary_heap container adaptors along the lines of std::stack, std::queue, and std::priority_queue, allowing parameterization over (e.g., stack-based container). Subsequent discussion indicates that there are some impracticalities in doing so, namely that it could invalidate other policies (e.g., stability). - Phil Endecott suggested rewriting some heaps (b_heap and d_ary_heap) in terms of more general algorithms operating on a (Random Access) Range in order to support the formulation of heap structures on other memory structures. Doing this would also help support the definition of heaps that satisfied Thorsten's request. I strongly recommend investigating Phil's suggestion, but this is not a barrier to acceptance. This feature could be added in future revisions of the library. I'd like to thank the community members who took the time to review Tim's work and especially those that submitted formal reviews. I'd also like to thank Tim (again) for his contributions and patiently answering our questions and addressing our comments. Andrew _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

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[review][assign] Formal review of Assign v2 begins 15th June
by John Bytheway 14 Jun '11

14 Jun '11

The formal review of the Assign v2 library upgrade by Erwann Rogard starts tomorrow, June 15th and is scheduled to continue until June 24th. About Assign v2 =============== Assign v2 is an upgrade of Boost.Assign (1.0) that redefines its functionality, with optional C++0x support and new features. It is a compact interface for executing the repetitive tasks of assigning or inserting container elements. Please see the change log (linked below) for more detail on the motivation for this library and pointers for navigating the documentation. Where to get it =============== The documentation is online at: <http://svn.boost.org/svn/boost/sandbox/assign_v2/libs/assign/v2/doc/html/in…> With the change log at: <http://svn.boost.org/svn/boost/sandbox/assign_v2/libs/assign/v2/doc/html/bo…> The Assign v2 source can be found in the Boost sandbox at: <http://svn.boost.org/svn/boost/sandbox/assign_v2/> or downloaded from: <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=assign…> Review guidelines ================= Reviews should be submitted to the developer list (boost(a)lists.boost.org) with '[assign]' in the subject. Or if you don't wish to for some reason, you can send them privately to me. If so, please let me know whether or not you'd like your review to be forwarded to the list. All reviews are appreciated, even if you don't have time for an in-depth study. The Assign v2 library consists of several largely independent components: Reference containers and chaining, container modification and generation, and conversion of ranges to containers. If you wish, feel free to review and even vote on these separately. For your review you may wish to consider the following questions: - 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? And finally, every review should answer this question: - Do you think the library should be accepted as a Boost library? Be sure to say this explicitly so that your other comments don't obscure your overall opinion. More detail on the review process is available at: http://www.boost.org/community/reviews.html John Bytheway Review Manager

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[boost] [review] Heaps
by Andrew Sutton 31 May '11

31 May '11

All, I'd like to announce the beginning of the review of the Heap library, written by Tim Blechmann, and resulting from Tim's 2010 Google Summer of Code project The library implements a number of different heaps (or priority queues) including, a binary heap, d-ary heap, binomial heap, fibonacci heap, pairing heap, and skew heap. The library also provides an adaptor to make heaps mutable, allowing a programmer to modify a value and update its position within the heap. The library also also supports stability, ensuring that elements pushed into a heap with the same priority are popped in the same order. The library is not targeted in any specific domain nor directly related to any specific libraries, but intended to be a collection of general purpose data structures (not unlike the Boost.Unordered library). The documentation and source code can be downloaded from here: Documentation: http://tim.klingt.org/boost_heap Code: http://tim.klingt.org/git?p=boost_heap.git;a=snapshot;h=HEAD;sf=tgz Unlike previous reviews, this review will be assisted by a code review application, Code Collaborator (by SmartBear). The product was tested during a BoostCon session, and we are eager to see how well it scales to a community review. You can use the link below to access and review the Heap library. http://demo.smartbear.com/boost/go?page=ReviewDisplay&reviewid=4 The application allows line-by-line comments of the submitted source code in addition to providing features for general defect and issue reporting. If you are interested in using this system, we will have to register you as a user of the site. You can request access by replying to this message. I'm still learning my way around the system, so there are bound to be some missteps along the way :) If you are not interested in using the system, then feel free to send email like any other review. Reviews of the library should address the following questions. 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? And finally, every review should answer this question: Do you think the library should be accepted as a Boost library? Be sure to say this explicitly so that your other comments don't obscure your overall opinion. Please note that some questions may be easier to answer in email than with the review tool. As always, reviews are important to the continued quality of the Boost C++ Libraries. Thank you in advance for your comments and contributions. Andrew PS. The review was slated to start on Sunday, but I was not able to make the announcement until today. _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

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Boost Steering Committee
by Beman Dawes 27 May '11

27 May '11

There was a special session Friday morning at BoostCon 2011 to announce the formation of a Boost Steering Committee. The slides from that session have been annotated to make them more comprehensible to those not present. See http://tinyurl.com/3l27o3q (There is also a link on steering.boost.org, but DNS isn't resolving that yet for me. Instead use https://sites.google.com/a/boost.org/steering/) We haven't yet decided anything beyond what is on the slides, so it will take a bit of time before details emerge. As the slides mention, the first job of the steering committee is to design of its own operating procedures and policies. Input from the Boost community will help form those procedures and policies. The steering committee is an important change in the way Boost operates! We hope it will position Boost to continue to grow and prosper. --The Boost Steering Committee Beman Dawes Dave Abrahams Hartmut Kaiser Jeff Garland Jon Kalb Marshall Clow Robert Stewart Steven Wantanabe

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[review][autoindex] AutoIndex review result
by Daniel James 24 May '11

24 May '11

The AutoIndex reviews were unanimously in favour of inclusion so it has been accepted into Boost. Reviews were submitted by: Edward Diener, Paul A. Bristow, Barend Gehrels and Hartmut Kaiser. Artyom also took part. Some of the general issues that were raised: The name should be more consistent. There was a little confusion about installation, but this should be easier once it's part of boost. Since it works at the docbook level it can be a bit confusing for a pure quickbook user. We might need to add extra support to quickbook - possibly in the form of a template library. There was some confusion about the integration of the different documentation tools, e.g. the use of <quickbook-define> to optionally include content in quickbook, using 'xinclude' to include doxygen documentation in quickbook. I think this is more of a weakness of the quickbook documentation. A few reviewers wanted finer grained control over where index terms are inserted. It isn't clear how this could be done without adding too much complexity. Adding processing instructions to the xml is one possibility. The C++ header scanner picks up too many symbols for spirit (and will possibly do so for other libraries), some kind of annotation or configuration might help. Thanks to everyone who participated in the review, and to John Maddock for developing AutoIndex, Daniel James

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Review Wizard Report for May 2011
by Ronald Garcia 23 May '11

23 May '11

============================================== Review Wizard Status Report for May 2011 ============================================== News ==== 1. Process Library Rejected 2. Phoenix Library Accepted 3. XInt Library Rejected 4. Type Traits Extensions Accepted 5. Locale Library Accepted 6. Convert Library Withdrawn 7. Conversion Library Accepted Provisionally 8. Context Library Accepted Provisionally 9. Boost 1.46.1 Released Revised Libraries: Asio, Filesystem, Fusion, Graph, ICL, Math, Polygon, Proto, Property Tree, Signals2, TR1, Unordered Revised Tools: Quickbook Open Issues =========== The following libraries have been reviewed and await reports from their review managers: * AutoIndex(Tool) - reviewed May 2011; review manager: Daniel James. The following libraries have been accepted to Boost, but have not yet been submitted to SVN: * GIL.IO - accepted January 2011; author: Christian Henning. * Type Traits Extensions - accepted March 2011; author: Frederic Bron. The following libraries have been accepted and submitted to SVN, but have not yet appeared in a release: * Phoenix - accepted March 2011; author: Joel de Guzmann. * Move - accepted February 2011; author: Ion Gaztanaga. * Geometry Library - accepted November 2009; author: Barend Gehreis et al. * Ratio - accepted October 2010; author: Vicente Botet. * Chrono - accepted January 2011; author: Vicente Botet. The following libraries have been accepted provisionally to Boost, but have not been submitted for mini-review and full acceptance: * Switch - accepted provisionally January 2008; author: Steven Watanabe. * Log - accepted provisionally March 2010; author: Andrey Semashev. * Context - accepted provisionally May 2011; author: Oliver Kowalke. General Announcements ===================== As always, we need experienced review managers. The review schedule has grown substantially but we have few volunteers, so manage reviews if possible and if not please make sure to watch the review schedule and participate. 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 cmu dot edu" and "phillips at pacific dot mps dot ohio-state dot edu" 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 before we do that, 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) * Pimpl (M) * Endian * Conversion * Sorting (M) * AutoBuffer * Containers * Lockfree * Fiber (M) * Quaternions, Vectors, Matrices (M) * Stopwatches * Variadic Macro Data (M) * Type Traits Introspection * Block Pointer (M) * Heaps * Assign v2 * Network (M) * Algorithm * Local (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. Pimpl ----- :Author: Vladimir Batov :Review Manager: Needed :Download: | `Boost Vault <http://www.boost-consulting.com/vault/index.php?action=downloadfile&fil…>`__ | http://www.ddj.com/cpp/205918714 (documentation) :Description: The Pimpl idiom is a simple yet robust technique to minimize coupling via the separation of interface and implementation and then implementation hiding. This library provides a convenient yet flexible and generic deployment technique for the Pimpl idiom. It's seemingly complete and broadly applicable, yet minimal, simple and pleasant to use. Endian ------ :Author: Beman Dawes :Review Manager: Joel Falcou :Download: http://svn.boost.org/svn/boost/sandbox/endian/ :Description: Conversion ---------- :Author: Vicente Botet :Review Manager: Gordon Woodhull :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=co…>`__ :Description: Generic explicit conversion between unrelated types. Boost.Conversion provides: * a generic ``convert_to`` function which can be specialized by the user to make explicit conversion between unrelated types. * a generic ``assign_to`` function which can be specialized by the user to make explicit assignation between unrelated types. * conversion between ``std::complex`` of explicitly convertible types. * conversion between ``std::pair`` of explicitly convertible types. * conversion between ``boost::optional`` of explicitly convertible types. * conversion between ``boost::rational`` of explicitly convertible types. * conversion between ``boost::interval`` of explicitly convertible types. * conversion between ``boost::chrono::time_point`` and ``boost::ptime``. * conversion between ``boost::chrono::duration`` and ``boost::time_duration``. Sorting ------- :Author: Steven Ross :Review Manager: Needed :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=al…>`__ :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. AutoBuffer ---------- :Author: Thorsten Ottosen :Review Manager: Robert Stewart :Download: http://www.cs.aau.dk/~nesotto/boost/auto_buffer.zip :Description: Boost.AutoBuffer provides a container for efficient dynamic, local buffers. Furthermore, the container may be used as an alternative to std::vector, offering greater flexibility and sometimes better performance. Containers ---------- :Author: Ion Gaztanaga :Review Manager: John Maddock :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=bo…>`__ :Documentation: `Boost Sandbox <http://svn.boost.org/svn/boost/sandbox/move/libs/container/doc/html/index.h…>`__ :Description: Boost.Container library implements several well-known containers, including STL containers. The aim of the library is to offers advanced features not present in standard containers or to offer the latest standard draft features for compilers that comply with C++03. Lockfree ------------------ :Author: Tim Blechmann :Review Manager: Hartmut Kaiser :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=bo…>`__ :Documentation: http://tim.klingt.org/boost_lockfree/ :Description: Lockfree provides implementations of lock-free data structures. Lock-free data structures can be accessed by multiple threads without the necessity of blocking synchronization primitives such as guards. Lock-free data structures can be used in real-time systems, where blocking algorithms may lead to high worst-case execution times, to avoid priority inversion, or to increase the scalability for multi-processor machines. Lockfree provides: * boost::lockfree::fifo, a lock-free fifo queue * boost::lockfree::stack, a lock-free stack Fiber ----- :Author: Oliver Kowalke :Review Manager: Needed :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=bo…>`__ :Description: C++ Library for launching fibers (micro-threads) and synchronizing data between the fibers. 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. Stopwatches ----------- :Author: Vicente Botet :Review Manager: Anthony Williams :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=st…>`__ :Description: On top of the standard facilities of Boost.Chrono, Stopwatches provides: * Stopwatches: A facility to measure elapsed time with the ability to start, stop, suspend, or resume measurement. * Stopwatch concept * Scoped helper classes allowing to pairwise start/stop operations, suspend/resume and resume/suspend a Stopwatch. * stopwatch, model of Stopwatch capturing elapsed Clock times. * stopwatch_accumulator, model of Stopwatch capturing accumulated elapsed Clock times. * Stopclocks: a complete time reporting package that can be invoked in a single line of code. * stopwatch_reporter, convenient reporting to an output stream (including wide char streams) of the elapsed time of models of Stopwatch results. * stopclock<Clock> shortcut of stopwatch_reporter<stopwatch<Clock>> Variadic Macro Data ------------------- :Author: Edward Diener :Review Manager: Needed :Download: `Boost Sandbox <http://svn.boost.org/svn/boost/sandbox/variadic_macro_data/>`__ :Description: The variadic_macro_data library adds support and functionality for variadic macros to Boost as well as integrating variadic macros with the Boost PP library without changing the latter library in any way. Type Traits Introspection ------------------------- :Author: Edward Diener :Review Manager: Joel Falcou :Download: `Boost Sandbox <http://svn.boost.org/svn/boost/sandbox/tti/>`__ :Description: The TTI library, which is an abbreviation for the 'Type Traits Introspection' library, allows a programmer to introspect at compile time the inner elements of a C++ type. The introspection process depends on specifying the name of the inner element by different macros for different types of elements, and then using a generated metafunction to determine whether that element exists within the enclosing type. The inner elements which can be introspected are type, class template, member data, member function, static member data, and static member function. Block Pointer ------------- :Author: Phil Bouchard :Review Manager: Needed :Download: `Boost Sandbox <https://svn.boost.org/svn/boost/sandbox/block_ptr/>`__ :Description: Deterministic memory manager of constant complexity capable of handling cyclic collections. Heaps ----- :Author: Tim Blechmann :Review Manager: Andrew Sutton :Download: http://tim.klingt.org/git?p=boost_heap.git;a=snapshot;h=HEAD;sf=tgz :Description: The Heap library is an implementation of priority queues, data structures that order their elements priority. They are useful in a number of different applications especially graph search algorithms and queuing systems. Whereas the STL provides a class template std::priority_queue, Boost.Heap implements data structures with different features and performance characteristics. One key feature is the inclusion of "mutable" heaps, which allow the priorities of enqueued objects to modified and their position in the queue updated. The heaps in the library also support merging, stable sorting, and equality and less-than comparison. Assign v2 --------- :Author: Erwann Rogard :Review Manager: John Bytheway :Download: `Boost Sandbox <http://svn.boost.org/svn/boost/sandbox/assign_v2>`__ :Description: This library is an upgrade of Boost.Assign 1.0 that redefines its functionality, with optional C++0x support and new features. It expresses repetitive statements for assigning or inserting elements via a basic grammar. Network ------- :Author: Dean Michael Berris :Review Manager: Needed :Download: http://cplusplus-soup.com/2011/04/18/cpp-netlib-0-9-0-released/ :Description: This is a library that provides application layer protocol support using modern C++ techniques. It is light-weight, fast, cross-platform and is intended to be as easy to configure as possible. Algorithm --------- :Author: Marshall Clow :Review Manager: Dave Abrahams :Download: `Boost Sandbox Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=Boost.…>`__ :Description: Boost.Algorithm is a collection of general purpose algorithms. While Boost contains many libraries of data structures, there is no single library for general purpose algorithms. Even though the algorithms are generally useful, many tend to be thought of as "too small" for Boost. An implementation of Boyer-Moore searching, for example, might take a developer a week or so to implement, including test cases and documentation. However, scheduling a review to include that code into Boost might take several months, and run into resistance because "it is too small". Nevertheless, a library of tested, reviewed, documented algorithms can make the developer's life much easier, and that is the purpose of this library. Local ----- :Author: Lorenzo Caminiti :Review Manager: Needed :Download: `Boost Sandbox <http://svn.boost.org/svn/boost/sandbox/local/>`__ :Description: This library supports local functions, local blocks, and local exits Libraries under development =========================== See http://svn.boost.org/trac/boost/wiki/LibrariesUnderConstruction for a current listing of libraries under development.

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[boost] Boost.Context review result
by Vicente BOTET 14 May '11

14 May '11

Hi, this was my first experience as review manager and it has been more difficult than I had expected. Apologies if I forget some important things or I misunderstood others. I hope that the major points have been taken in account. Here it is the result of the Boost.Context review. The library is accepted provisionally and will need to address some mandatory points before a mini review (4/5 days). There were not too much complete reviews (5) but globally all the reviewers voted for acceptation and two subject to some major redesign modifications. I hope I didn't miss somebody. YES Gordon Woodhull YES/Cnd Giovanni Piero Deretta YES Artyom YES Nat Linden YES Phil Endecott YES/Cnd, Jeffrey Lee Hellrung, Jr Thanks to all the review participants Gordon Woodhull, Giovanni Piero Deretta , Artyom, Nat Linden, Holger Grund, Phil Endecott, Jeffrey Lee Hellrung, Jr.. Special thanks to Giovanni Piero Deretta showing some major flaws in the global design and Holger Grund for showing a (possible) major bug on the Windows implementation. I know Oliver that you have already redesigned your library, but if there are points that you have not been addressed yet or have some difficulties addressing them, I will suggest you to work closely with Giovanni, he know well the domain and have a lot of good ideas, and exchange on this ML. You should follow up more closely the discussions during the mini review and even try to get feedback from the ML posting how you see your redesigned library. Point to be addressed before the mini review: Design 1. Separation of the context class in two interface: - A C-like interface that defines a POD struct that is memcpy-able and that can be implemented either using platform libraries, as ucontext, fibers or directly using assembler when a robust implementation is available. The context swap implementation don't need to save the signals as ucontext does. The following is just for illustrations purposes. struct boost_context; typedef void boost_context_fn_t(intptr_t); extern "C" void boost_context_make(boost_context* ctx, boost_context_fn_t * f, intptr_t p, ...); extern "C" void boost_context_swap(boost_context* from, boost_context const* to); extern "C" intptr_t boost_context_destroy( boost_context* fc); boost_context_make is a merge of get_context with make_context + some fields assignations. "A user will have lower expectations from such a low level API and at the same time will give more freedom for other people to implement on top of it higher abstractions as Boost.Corutines, Boost.Fibers ..." - A non-copiable but movable safe context class on top of the low level C-like interface, that will provide modern and efficient C++ interface, that is usable by a user in a safe way. The safe context class would just be one of the client of the C-like interface, other library authors could either use the underlying C-like API directly or the class context depending on wether they need the speed or safety. * The context class will not be templated any more, and the use of type erasure will ensure that. * The constructor will accept any C++ callable, function pointers, functors, ... * At this high level interface, the function provided by the user could throw exceptions, and the library must wrap the user function and needs to store the exception raised and provide an interface to retrieve them. 2. The stack implementation must ensure that the stack is unwound before it is destroyed. A stack should only be safely deallocated if either has been completely unwound or if it doesn't own any resources. A basic stack without protection seems mandatory. For debug purposes it has been required to provide some stack usage functions that allow to know the max size used for example. Implementation 3. The assembler implementation on Windows must be disallowed if the ABI bug reported by Holger is confirmed. As far as Windows provides a fiber implementation that is as efficient as the assembler one, the assembler implementation is not mandatory and the user of the provided Windows fiber is a preferable choice. 4. Most of the 'throw' statements in the context class should actually be asserts. 5. The provided stack should be used to store any context parameters as far as no major impediment is found during the implementation. This will avoid further allocations on the safe context class. Documentation 6. The documentation is very minimalist and should be expanded with a discussion on context switching and use cases. Take care of all the grammar/spelling improvements suggested by the reviewers (It will be great if Jeffrey could review the documentation before the mini-review). Some user land examples should be provided (why not the yield example). 7. The concept of (Movable) Stack must be clearly defined, as it is done in the standard, using expression requirements with semantic constraints. 8. The assembler implementation should be carefully documented, so others could maintain the code and add other implementations if needed. 9. Some performance measure should be added. Providing the number of cycles on each implemented platform would be nice. Build system 10. The default build on a platform must work (It must be ABI compatible with the underlying platform) and take care of the specific features. Of course, the build needs to support cross compiling, so the user should be able to override the default values. Others points that are not required but that can make the library more usable or efficient: 1. The assembler implementations could be simplified if the context itself was represented as a single pointer to the top of the stack. This would save some instructions to move the source address from the stack return address to the context struct and back. 2. Instead of supporting a 'fc_link' a-la ucontext, have the callback function return a new context (it is void now). 'fc_link' is useful only on some limited cases (usually when you have an external scheduler managing your contexts), while the having the callback return the 'next continuation' has more applications (note that fc_link can be implemented easily in term of the continuation returning variant, but the reverse is harder). This will be very useful, for example, to implement some kind of 'exit_to' functionality (unwind the stack and restore another context), a key piece for safe context destruction. 3. Give to boost_context_swap the ability to exchange a parameter with the other context: boost_context_parm_t boost_context_swap( boost_context * ofc, boost_context const* nfc, boost_context_parm_t parm) where boost_context_parm_t is either union boost_context_parm_t { void * ptr; int int_; }; or simply intptr_t; boost_context_swap saves the current context in ocf and restores the context ncf as usual; additionally, if ofc was 'captured' on a call to boost_context_swap, this call will return the value of parm on the original context. This extra parameter is equivalent to the second parameter of longjmp. If ofc was created with boost_context_swap, 'parm' will be an extra parameter to the function. Note that this can be potentially implemented with little or no overhead. 4. Add a variant of boost_context_swap that allows executing a function on the destination context (in this case 'parm' would be passed parameter to this function. This is mostly useful for injecting an exception on the destination context. This can be potentially implemented on top of the existing functionality, but would slow down every context switch; a possible efficient implementation would manipulate the destination stack to add a call to the function on top of it, so that the cost is paid only when required. 5. Add a current context function (thread local). Vicente Review Manager _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

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[boost] [Review] Boost.Convert, review manager analysis
by Edward Diener 06 May '11

06 May '11

As previously stated Vladimir Batov decided to withdraw his library at the end of the review period from consideration for inclusion into Boost and I had announced this and the fact that because of this the library would not be accepted. Nonetheless I want to give my analysis of the reviews and the issues both pro and con of the reviewers. I also want to give some of my own thinking on these issues. There were few reviews of the library but much late discussion in the final day of the review period and just afterward. There were 2 reviews which voted to accept Convert ( Artyom Bellis, Alfredo Correa ), 3 reviews which voted not to accept Convert ( Jeroen Habraken, Thomas Heller, Hartmut Kaiser ), 1 review which would have accepted Convert but qualified that only if lexical_cast could not be extended instead ( Rob Stewart ), 1 review which would have accepted Convert with large scale changes ( Gordon Woodhull ), and one mention, not a formal review, of acceptance until something else came along but with perhaps a later change of mind ( Paul Bristow ). There was also one review sent to me personally by Barend Gehrels, after Vladimir Batov withdrew his library, which voted not to accept Convert. There were also a number of people who raised doubts and objections to Convert in various ways without giving a formal review. It is all these issues raised by reviewers and commenters I want to discuss next. Vladimir Batov was responsive to nearly all of those issues but I want to enumerate them and give my own thoughts about them as I read reviews and comments. A number of people wanted lexical_cast to be extended instead of a new library. This certainly is a valid viewpoint. But I believe that the lexical_cast library is set as it is until someone takes it over from its original author and is willing to change it. I think it is better to review the library under discussion rather than to hope that something else can be changed in the future. There was an issue of the basic syntax which many people did not like. Instead of the syntax of 'convert<dest>::from(source)' there were a number of people who wanted to see 'convert<dest>(source)' instead, largely becaused it matched the 'lexical_cast<dest>(source)' syntax. Vladimir Batov explained why he used the syntax he did. I think in this case it is reasonable. Again this is an issue in relation to lexical_cast, and I saw no real significant difference between the syntaxes on a basis of practical use. The main issue brought out by many people is whether a single function can encompass successfully all of the functionality which Convert wished to encompass and whether this functionality both worked smoothly with everything others wished to do with the functionality. Here there were many valid objections and I will attempt to enumerate them: 1) The return value of the convert function is really many different returns, and this is done through implicit conversions of the actual return type. This was mentioned most eloquently by Thomas Heller. It is quite natural to assume that the return value of a successful call to 'convert<dest>::from(source)' would be a 'dest' object but instead it is a value which has an implicit conversion to 'dest'. This works when passing the value to ordinary functions but does not when passing the value to template functions. As Vladimir Batov mentioned one can use the 'value()' member function of the return value, and presumably also one can use a 'static_cast<dest>' also, to force the exact 'dest' object to be passed, but I also viewed this as a negative way to work, and a very valid objection to the way Convert was designed. To me it was not just a matter of confusion to the end-user but of a naturalness of use. A convert-type interface should have some function where, if the convert is successful, the actual result of the conversion is returned, and not some intermediate value with an implicit conversion. 2) The Convert library uses a stream-based method to do conversions but wanted to leave the door open for other methods. Part of the extended syntax of the library works with stream manipulators and locales. A very valid point was brought up, again by Thomas Heller, that it is not clear how the extended syntax is supposed to work with and affect non-stream based specializations of the basic convert template. Even the method of extending the library in this way, rather than just providing stream-based operators for a given type, is open to much doubt as valid C++ and largely left unexplained in the documentation. 3) The syntax for the stream-based and locale additions to the library's functionality was found odd by many people. The term 'wacky' was often used and Vladimir Batov did defend his choice about it well. Nonetheless it is a valid issue to consider whether the extended syntax is easy for a person to use. I found the syntax for using iostream manipulators quite natural, and the syntax for locales and other functionality such as throwing behavior less natural. Again I do not want to get too caught up in syntactical issues but I did understand the issues brought up by others regarding this. 4) The method of using the convert function in algorithms was criticized. Some people expressed their wish that a placeholder syntax, as used by other Boost libraries, be used. I actually found the way Convert does this as pretty elegant, there were two syntaxes which worked, but could understand others liking for the placeholder syntax. 5) The use of a default value, the issue of a default constructor, and the differing results when a conversion fails or not, received much discussion, especially at the official end of the review period and afterward, and I appreciate reading all of the discussions. I do not want to specifically go into each one, other than to say that I think this has basically to do with the issue of having a single function do everything which could not easily cover all the different scenarios mentioned for actual use. There were other valid concerns which are related to just a need for more complete documentation. Vladimir Batov responded to most of them. Here I will enumerate them: 1) Rob Stewart in his review mentioned many documentation corrections related to grammar, spelling etc. 2) What locale is being used by default is not explained. 3) The reference is very incomplete. 4) The section for extending the library is unclear and incomplete. Finally there were valid concerns relating to getting Convert to work properly. Some of these related Convert and lexical_cast and noted the differences. A few others mentioned things which just did not work properly in the actual conversion and again Vladimir Batov said he would look at these issues. Barend Gehrels sent me a late review, which he did not want to post to the mailing list because Vladimir Batov had already withdrawn is library, in which he said that he had some technical problems adapting a Boost.Geometry type to work with Convert. I think these are all technical issues which can be resolved. Many other people had specific incisive remarks during the review period but I can not list them all. That does not mean those remarks were ignored by me in any way, as I read and attempted to digest what everyone had to say. Final remarks: I would like to bring some clarity to the issues which may have forced Vladimir Batov to essentially withdraw his library at the end of the review period from consideration and which led to much comment and criticism about the library. This is my purely personal take on the library, but it is based on my technical understanding of the issues involved. The main issue with the library is that the 'single function fits all scenarios' works much less well in practical use than the author supposed, even as I understood the reason for simplicity which caused him to pursue this path. There really needs to be a function that simple returns the converted value upon success. Overloaded versions of that function, or differently named functions, can return other specific things. Where there is a great attraction to a return value which can be implicitly converted to other values, I think this attraction given practical use is somewhat illusory. While I did not enjoy some of the harsher remarks made by Thomas Heller in his review of the library about the design of Convert ( and I do not think he really meant them as harshly as they may have sounded ) he did rightly point out that the 'overloaded' return value is an impediment to a cleaner design which would allow one to use the right convert function given the possibilities which the library wants to accomplish. I know there has been many subsequent discussions about a set of functions that can replace the single function in Convert depending on how Convert can be used, and I do not myself want to get in the middle of this debate, but once there is an understanding of what needs to be done, I really think the library can be designed to appeal to end-users in a better way. The second issue in my mind is that the library attempts to do too much given the way it was designed. If the focus is simply a library which does stream-based conversion between strings and objects ( both ways ) I personally think it would be much better. Once you look for non-stream based conversions you have to consider more carefully how the stream-based syntax and locales should be integrated with the library. Once you look for type to type conversions rather than string to type and type to string conversions you have to design a good general facility for specifying how this is done within the functions you provide. This is a much bigger job of thinking about design, unless you are simply providing a very generalized shell with little real functionality built-in. I am not saying the author of the library has not thought about these issues, but my impression is that they have not been addressed carefully. Just in case anyone wanted to know, and also so that Vladimir Batov does not feel so bad about withdrawing the library from consideration at the end of the review period, I would have rejected the library for inclusion into Boost given the reviews and comments of others and my own perceptions of the issues involved. But I think the author has still done a fine job and is close to having a library which could be included as a part of Boost. Although it is hard work, it has been a pleasure to be a review manager of this library and I thank everyone involved and especially the author of the Convert library himself. Edward Diener _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

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