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[1.51][program_options] Changesets not merged to release
by Andrey Semashev 26 Jul '12

26 Jul '12

Hi, I've noticed that changesets 79280 and 79283 have not been merged to the release branch. The first fixes compilation with STLPort and the second one removes warnings. Both look quite harmless and have been committed to trunk for quite a while. I don't see any regressions in tests caused by these changes. Can these be merged to trunk? I can do the merge, if permitted.

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BlueGo Beta 0.0.1
by Julian Amann 26 Jul '12

26 Jul '12

I build a small tool which builds boost libraries using Visual Studio 2010 x64. It can be downloaded from here: http://vertexwahn.de/ You just have to start the application and click the "Download and Build Boost 1.50.0 with Visual Studio 2010 x64" button - everything else should work automatically. The application downloads the current boost library and builds it. Julian

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[iterators]: collection_keys and collection_values
by Igor Lubashev 26 Jul '12

26 Jul '12

I'd like to propose adding collection_keys and collection_values to iterators library. ======== Motivation ======== I find myself very often having to iterate over all keys or values of a map (or multimap). The best I can do is to use BOOST_FOREACH to iterate over the collection value_type pairs and then work with .first or .second. That makes for awkward and unclear code. BOOST_FOREACH( const foo_bar_map_t::value_type &foo_bar_pair, my_map ) { baz(foo_bar_pair.second); } Instead, I'd like to do something like: BOOST_FOREACH( const bar_t &bar, collection_values(my_map) ) { baz(bar); } BOOST_FOREACH( const foo_t &foo, collection_keys(my_map) ) { baz(foo); } ======== Proposal ======== Add this to iterators library as collection_iterators.hpp Thanks, - Igor #ifndef .... #define .... #include <boost/iterator/transform_iterator.hpp> namespace boost { namespace detail { template<typename CollectionT> struct key_function : public std::unary_function<const typename CollectionT::value_type&, const typename CollectionT::key_type&> { typename key_function::result_type operator()(typename key_function::argument_type p) const { return p.first; } }; template<typename CollectionT> struct value_function : public std::unary_function<const typename CollectionT::value_type&, const typename CollectionT::mapped_type&> { typename value_function::result_type operator()(typename value_function::argument_type p) const { return p.second; } }; template<typename CollectionT, typename AdapterF> class collection_adapter { const CollectionT &c; public: typedef boost::transform_iterator<AdapterF, typename CollectionT::const_iterator> const_iterator; typedef const_iterator iterator; collection_adapter(const CollectionT &c) : c(c) {} const_iterator begin() const { return boost::make_transform_iterator(c.begin(), AdapterF()); } const_iterator end() const { return boost::make_transform_iterator(c.end(), AdapterF()); } }; } // Adapter for map-like collection -> iterable keys collection template<typename CollectionT> const detail::collection_adapter<CollectionT, detail::key_function<CollectionT> > collection_keys(const CollectionT &c) { return detail::collection_adapter<CollectionT, detail::key_function<CollectionT> >(c); } // Adapter for map-like collection -> iterable values collection template<typename CollectionT> const detail::collection_adapter<CollectionT, detail::value_function<CollectionT> > collection_values(const CollectionT &c) { return detail::collection_adapter<CollectionT, detail::value_function<CollectionT> >(c); } } // namespace boost #endif // ....

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website/docs: link broken
by Markus Werle 25 Jul '12

25 Jul '12

Hi! On http://www.boost.org/doc/libs/1_50_0/libs/scope_exit/doc/html/scope_exit/Ge… g_Started.html There is a link to http://www.boost.org/doc/libs/1_50_0/libs/scope_exit/doc/html/scope_exit/Tu… al.html which is broken. Error message is: 404 Not Found File "/home/grafik/www.boost.org/archives/live/boost_1_50_0/libs/scope_exit/doc /html/scope_exit/Tutorial.html" not found. Unable to find file. Markus

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Re: [boost] Macro for BOOST_NO_NUMERIC_LIMITS_MAX_DIGITS10 or use BOOST_NO_NUMERIC_LIMITS_LOWEST
by Stewart, Robert 24 Jul '12

24 Jul '12

John Maddock wrote: > > >> is there a way to don't include all the deprecated macros? > > Whoa - interesting question. > > I don't know of one. > > > > However, all the deprecated macros are defined (I > > _believe_) in one place, in boost/config/suffix.hpp > > Making it so none of them are defined _should_ be > > straightforward. > > > >Could I suggest to define all of them in a specific > >boost/config/deprecated.hpp file, so that we can add a > >deprecated warning when the file is included. +1 > I think it's too soon for that - as things stand you would > basically be injecting that warning into every Boost header > that includes boost/config.hpp. Aren't there some that have been deprecated for long enough to get that sort of treatment? IOW, create a mechanism for complaining about the use of old names and a policy for how long old names are defined without complaint, how long with complaint, and how long before they are removed. For example, newly renamed macros might be kept in config/suffix.hpp for four releases before moving them to config/deprecated.hpp. Then, names in deprecated.hpp might remain for two releases before removing them altogether. > Besides I don't see what harm defining the old names does? If you can't ever remove the old names, then the set of names that can appear in Boost code grows uncomfortably large. _____ Rob Stewart robert.stewart(a)sig.com Software Engineer using std::disclaimer; Dev Tools & Components Susquehanna International Group, LLP http://www.sig.com ________________________________ IMPORTANT: The information contained in this email and/or its attachments is confidential. If you are not the intended recipient, please notify the sender immediately by reply and immediately delete this message and all its attachments. Any review, use, reproduction, disclosure or dissemination of this message or any attachment by an unintended recipient is strictly prohibited. Neither this message nor any attachment is intended as or should be construed as an offer, solicitation or recommendation to buy or sell any security or other financial instrument. Neither the sender, his or her employer nor any of their respective affiliates makes any warranties as to the completeness or accuracy of any of the information contained herein or that this message or any of its attachments is free of viruses.

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[TypeErasure]
by Markus Werle 24 Jul '12

24 Jul '12

Hi Steven! I have one question: proto and spirit use _1, _2, etc. TypeErasure uses _a, _b, _c ... What was your reason to introduce yet another placeholder set? Markus

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[move] Implementing operator= in terms of pass-by-value and swap
by Krzysztof Czainski 24 Jul '12

24 Jul '12

Hello, Implementing the assignment operator (that is, the copy-, move- and other assignments) in terms of pass-by-value and swap is a common idiom [1]. {{{ T operator=( T b ) { swap(*this,b); return *this; } }}} If T is copy-constructible, the above works as a copy-assign. If T is movable, the above works as a move-assign. And for anything convertible to T the above assign will work (right?). Furthermore, this will also work for movable but not copyable classes (right?). It may not be the optimal version of assignment in some cases. In rare cases it might even be incorrect - for types like std::vector, which aren't expected to free reserved memory upon assignment. But assuming swap is a cheap operation, it should be close to optimal in many if not most cases. And in cases, where RVO kicks in, it may be even better than providing separate overloads of operator= for lvalues and rvalues [2]. Boost.Move docs [3] suggest writing the separate overloads of operator=, and in C++03 move emulation the macro BOOST_COPYABLE_AND_MOVABLE(classname) provides a third overload (necessary for the emulation to work in C++03). Should the user choose to write one overload of operator= in the pass-by-value version, he needs to use a different macro, that doesn't provide the additional overload of operator=. I found such a macro: BOOST_COPYABLE_AND_MOVABLE_ALT(classname), but no docs about it. I have the following suggestions, regarding Boost.Move: 1. Providing a macro, BOOST_MOVABLE(classname), that only provides the two needed conversion operators. Or if that is the purpose of BOOST_COPYABLE_AND_MOVABLE_ALT(classname), I couldn't find docs about it. And to avoid a macro entirely, maybe it is possible to provide a CRTP base class 'movable', that would provide these? 2. Now, that there's a separate macro, defining a movable class, it may make sense to add a separate macro for making a class noncopyable. And we already have a base class for that, if one wants to avoid a macro. 3. It would be nice if the docs [3] mentioned something about the alternative of providing only one operator= passing by value. [1] http://en.wikibooks.org/wiki/More_C%2B%2B_Idioms/Copy-and-swap [2] http://cpp-next.com/archive/2009/08/want-speed-pass-by-value/ [3] http://www.boost.org/doc/libs/1_50_0/doc/html/move/implementing_movable_cla… Regards, Kris

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Re: [boost] [type_erasure] [docs]contrast with boost::any
by Larry Evans 23 Jul '12

23 Jul '12

On 07/23/12 15:37, Larry Evans wrote: > On 07/18/12 00:13, Lorenzo Caminiti wrote: >> Hello all, >> >> *** The review of Steven Watanabe's proposed Boost.TypeErasure library >> begins on July 18, 2012 and ends on July 27, 2012. *** >> > The page: > > http://steven_watanabe.users.sourceforge.net/type_erasure/libs/type_erasure… > > says: > > x is approximately equivalent to a boost::any > > however, it doesn't say how te::any differs from boost::any. > > The attached shows that a boost::any can change it's > type, and, as such, is somewhat like boost::variant. > However, te::any, once it's created, cannot change > it's type, AFAICT. At least that's what the > attached code indicates when compiled with: > > #define SHOW_TE_FIXED_TYPE > A simplified version of that code (which doesn't require demangled_type_name), is attached. The attached also suggests that, when multiple placeholders are in the concept, the unary any *requires* a binding argument. This is shown by trying to compile the attachment with: #define SHOW_BINDINGS_MUST_BE_COMPLETE In contrast, the example here: http://steven_watanabe.users.sourceforge.net/type_erasure/libs/type_erasure… shows no binding is needed because the only placeholder in the concept is the default, _self. HTH. -regards, Larry

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[Review Request] array
by Brian Smith 23 Jul '12

23 Jul '12

Hi All, Based on the assumption that, almost no feedback is good feedback, I'd like to submit the array class for review. The requisite files are hosted at, https://github.com/BrianJSmith/Array Comment: The array class is a C++11 compatible implementation of static multidimensional arrays. Kind Regards Brian

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[TypeErasure] Forward constructors and binded types
by Vicente J. Botet Escriba 23 Jul '12

23 Jul '12

Hi,, In the example from the doc typedef mpl::vector< copy_constructible<_a>, copy_constructible<_b>, copy_constructible<_c>, constructible<_a(const _b&, const _c&)> > construct; std::vector<double> vec; int i = 10; double d = 2.5; tuple<construct, _a&, _b, _c> t(vec, i, d); any<construct, _a> v(get<1>(t), get<2>(t)); I don't see which type is constructed and stored in v and how this type is given. That is I don't see how _a is binded. Could you help me? Best, Vicente

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