June 2011 - Boost - lists.preview.boost.org

[serialization] or [spirit] JSON Archives
by Fernando Pelliccioni 08 Sep '11

08 Sep '11

Hi, After experimenting with Spirit.Qi to make a JSON parser, I had the need for a serializer. First, I thought I could serialize my model of JSON (json:: value, json: object, etc.), but that was not compatible with boost::serialization. I am currently writing a ARCHIVE for Boost Serialization, but I'm finding some problems in order to implement JSON correctly. The question is, does anyone know about some files to Boost Serialization already finished? I've seen the Archive made by Esteve Fernandez, but do not serve my purpose, because I just need JSON. I would like to develop a JSON parser which in turn is a compatible Boost Serialization serializer . Any ideas? Thanks and regards, Fernando Pelliccioni.

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Acknowledgement for Certs 4 Less
by Dave Abrahams 02 Sep '11

02 Sep '11

All--- For some time now, Boost has been using the CA-signed wildcard SSL certificate that was very generously donated by Certs 4 Less. I promised them, in return, that Boost would acknowledge them on our website, as we have done in the past for other donors. We acquired the certificate so we could accept e-payments for BoostCon, but in the end we decided to pay EventBrite to take payments for us... so as far as I know, the cert is only being used at the moment for https://svn.boost.org Two questions: 1. Where does the acknowledgement belong? 2. Can someone who knows how put it there? P.S. I would be very happy not to get separate answers to those, if someone who knows how to edit the website *and* an appropriate placement for the acknowledgement could just take care of it ;-) Thanks, -- Dave Abrahams BoostPro Computing http://www.boostpro.com

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New version of Boost.Algorithm (proposed) in the vault
by Marshall Clow 17 Aug '11

17 Aug '11

<http://www.boostpro.com/vault/index.php?action=downloadfile&filename=Boost.…> Changes since -008: * Better documentation all around - including doxygen. * Fixed typo-style bugs in all.hpp, and added tests to make sure they stay dead. * Better comments in clamp.hpp, and better tests. * The search algorithms now deal correctly with zero-length patterns and corpuses, and have tests for that. * The search algorithms now have tests for the compile-time assertions. * MSVC 10 compatibility Please download, try it out, and let me know! Thanks! -- Marshall Marshall Clow Idio Software <mailto:mclow.lists@gmail.com> A.D. 1517: Martin Luther nails his 95 Theses to the church door and is promptly moderated down to (-1, Flamebait). -- Yu Suzuki

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How to use BCP
by William Voorhees 17 Aug '11

17 Aug '11

I'm updating a small C program to take in a options from either environment variables, or a config file and having long heard of boost as a great resource decided to give the program_options module a try. Since the utility is small and I don't have any current plans for other boost functionality it doesn't make sense to include the full BOOST library, so I tried to use bcp to get only the files I'm interested in. I was able to get a subset of boost code that I should be able to use with bcp, however I don't know how to compile the program_options library for linking in my code. >From a bit of googling it looks like bjam is the build tool, but it doesn't seem to be included with the subset of files I have. How would I go about incorporating boost so that all of the necessary source and associated utilities are included for an end user to build from. I should be able to issue a series of simple commands (looks like ./bootstrap.sh and make) to build and install my library with statically linked in boost. -Will Voorhees

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numeric_cast
by Brandon Kohn 03 Aug '11

03 Aug '11

Hello, Recently I was creating a new numeric type which I wanted to use along with boost::numeric_cast. I read over the docs and examples and found that it seemed to support (at least partially) the notion of policy driven casting operations. I was unable to figure out how one might use a custom conversion or overflow policy along with the actual boost::numeric_cast<N>(x) function. In the end I created a workaround which seemed to work nicely: template <typename ConversionTraits, typename EnableIf = void> struct numeric_cast_traits { typedef def_overflow_handler overflow_handler; typedef UseInternalRangeChecker range_checker; typedef Trunc < typename ConversionTraits::source_type > rounding_policy; }; template <typename Target, typename Source> inline Target numeric_cast( Source arg ) { typedef boost::numeric::conversion_traits<Target, Source> conv_traits; typedef numeric_cast_traits< conv_traits > cast_traits; typedef boost::numeric::converter < Target , Source , conv_traits , typename cast_traits::overflow_handler , typename cast_traits::rounding_policy , boost::numeric::raw_converter< conv_traits > , typename cast_traits::range_checker > converter; return converter()(arg); } This change allowed me to easily customize the numeric_cast function for individual conversion types. Did I miss something in the official library? If not, would this change be something good to go in? Regards, Brandon Kohn

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Boost.Locale 'Status'?
by Joshua Boyce 27 Jul '11

27 Jul '11

I was wondering what the 'status' of the Boost.Locale library is now that it has been accepted into Boost. I can't see it on the SVN, what are the current plans for its integration into mainline Boost? Thanks.

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[Opaque] Request for interest in Opaque typedefs library emulation
by vicente.botet 27 Jul '11

27 Jul '11

Hi, I have started to play with a class to define opaque typedefs on funcdamental types. It is based on the C++ proposal " Progress toward Opaque Typedefs for C++0X" by Walter E. Brown http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1891.pdf and http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2004/n1706.pdf Please take a look on the preceding links to understand the motivation. Boost.Sericalization provide a BOOST_STRONG_TYPEDEF already, but in my opinon the implementation is not complete,as only the order operators are defined (But maybe I'm wrong). Evidently it can not provide everything we can have with a language approach, but IMO this could yet be useful. The library include two class templates (CRTP) to define opaque types: * public_opaque_type<OT,UT> : implicit conversion from OT to UT * private_opaque_type<OT,UT> : no conversion from OT to UT An opaque type (OT) is a new type, different from the underlying type (UT) and other OT. It defines explicit constructor from the UT, and defines all the operators the UT support but this time applied to the OT. To define a new OT with this mixin classes struct serial_number: public_opaque_type<serial_number, unsigned> { BOOST_OPAQUE_PUPLIC_FORWARD_CONSTRUCTORS(serial_number,unsigned); }; struct game_score: private_opaque_type<game_score, unsigned> { BOOST_OPAQUE_PRIVATE_FORWARD_CONSTRUCTORS(game_score,unsigned); }; In addition, defines macros that make this simpler BOOST_OPAQUE_PUBLIC_TYPEDEF(unsigned, serial_number); BOOST_OPAQUE_PRIVATE_TYPEDEF(unsigned, game_score); Next follows the definition of the public_opaque_type template <typename Final, typename T> class public_opaque_type : boost::totally_ordered< Final , boost::integer_arithmetic< Final , boost::bitwise< Final , boost::unit_steppable< Final , boost::totally_ordered< T, Final // public specific conversions , boost::integer_arithmetic< T, Final // public specific conversions , boost::bitwise< T, Final // public specific conversions > > > > > > > { protected: T val_; typedef public_opaque_type opaque_type; public: typedef T underlying_type; explicit public_opaque_type(const T v) : val_(v) {}; public_opaque_type() {}; public_opaque_type(const opaque_type & rhs) : val_(rhs.val_) {} public_opaque_type & operator=(const opaque_type & rhs) { val_ = rhs.val_; return *this; } public_opaque_type & operator=(const T rhs) { val_ = rhs; return *this; } T const& underlying() const { return val_; } T& underlying() { return val_; } operator const T & () const { return val_; } operator T & () { return val_; } #if 0 bool operator==(const opaque_type & rhs) const { return val_ == rhs.val_; } #endif bool operator<(const Final & rhs) const { return val_ < rhs.val_; } Final& operator+=(const Final & rhs) { val_ += rhs.val_; return static_cast<Final&>(*this); } Final& operator-=(const Final & rhs) { val_ -= rhs.val_; return static_cast<Final&>(*this); } ... }; I have started to make some tests and it works well for the moment. Limitations: * As we can not specialize the behaviour of static_cast/dynamic_cast the library sould provide two specific casts opaque_static_cast and opaque_dynamic_static_cast (Not yet implemented). * As operator.() can not be overloaded, it works transparently only for underlying types that don't defines member functions (C++ fundamental types, as int, char, ...). For the others an explicit use of the underlying() member function is needed :( * Others I have not catched yet :( Do you think it is worth continuing? Please, let me know if you see a error on the design. _____________________ Vicente Juan Botet Escribá http://viboes.blogspot.com/

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[filesystem] home_directory_path
by Jeff Flinn 24 Jul '11

24 Jul '11

In looking at implementing a portable home_directory_path function a few questions arise. Based on http://en.wikipedia.org/wiki/Home_directory, POSIX and other UNIX flavors 'appear' to be a straight forward use of the "HOME" environment variable. Does anyone have any experience where the "HOME" variable is not the proper source of the user's home directory? Windows NT and above have the "USERPROFILE" environment variable. Using this would be the easiest to use. But I've seen discussion that this may not always be properly defined, in particular if the user has reset their home directory to a non-system drive. I haven't tracked down it's availability on WinCE. Does anyone have experience with this platform? There is the windows GetUserProfileDirectory api function also available since NT4. This is in the Userenv.lib/dll, obviously adding a link dependancy. How are these sorts of system link dependencies handled? Through bjam? Or is it acceptable/better to use #pragma comment(lib,"Userenv.lib")? In looking at some client code using home_directory_path, I see that they generally are looking for the user's Desktop directory(Mac & Windows). Obviously this only makes sense on GUI platforms. The issue with merely getting this path via home_directory_path() / "Desktop" is IIRC, that at least on windows "Desktop" is localized and may not exist with that name on non-english localized systems. Windows has the SHGetFolderPath api. I need to look into Mac's native support. Any thoughts on the general usefulness of a portable desktop_directory_path? Thanks, Jeff

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RFC: type erasure
by Steven Watanabe 20 Jul '11

20 Jul '11

AMDG Over the last few months I've re-done my type erasure library from scratch, fixing a lot of the bad design decisions I made originally. Here's a basic sample of what you can do with it: simulate boost::any: type_erasure::any< mpl::vector<copy_constructible<>, typeid_<> > > x(10); simulate boost::function<void(int)>: type_erasure::any< mpl::vector<copy_constructible<>, typeid_<>, callable<void(int)> > > f(foo); The code is available from the Vault: http://tinyurl.com/3z9jcwp The library is nearly complete. I've included pre-built html documentation in the zip. Questions, comments, and criticism are welcome. In Christ, Steven Watanabe

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[local] Review request
by Lorenzo Caminiti 18 Jul '11

18 Jul '11

Hello all, I happy to announce that I have released Boost.Local 0.2.0 incorporating the many valuable suggestions that I have received from this mailing list. I would like to request to add Boost.Local to the review schedule and for any volunteer to be the review manager. Thank you! Boost.Local supports local functions, local blocks, and local exits for C++. For example: #include <boost/local/function.hpp> #include <boost/local/block.hpp> #include <boost/local/exit.hpp> #include <algorithm> #include <iostream> #include <cassert> int main() { double sum = 0.0; int factor = 10; void BOOST_LOCAL_FUNCTION_PARAMS(double num, const bind factor, bind& sum) { sum += factor * num; std::cout << "Summed: " << sum << std::endl; } BOOST_LOCAL_FUNCTION_NAME(add) add(100.0); size_t size = 2; double* nums = new double[size]; BOOST_LOCAL_EXIT(const bind& size, bind nums) { if (size && nums) delete[] nums; std::cout << "Freed array: " << nums << std::endl; } BOOST_LOCAL_EXIT_END nums[0] = 90.5; nums[1] = 7.0; std::for_each(nums, nums + size, add); // `add` as template parameter BOOST_LOCAL_BLOCK(const bind& sum) { assert(sum == 1975.0); // so far `sum` is 10*100+10*90.5+10*7=1975 std::cout << "Asserted summation: " << sum << std::endl; } BOOST_LOCAL_BLOCK_END return 0; } Documentation: http://svn.boost.org/svn/boost/sandbox/local/libs/local/doc/html/index.html Source code: http://svn.boost.org/svn/boost/sandbox/local/ Release Notes for Version 0.2.0 (2011-05-14) 1. Replaced parenthesized syntax with variadic and sequencing macro syntaxes. 2. Profiled library performances against other approaches. 3. Replaced virtual functor trick with casting functor trick (for smaller run-time). 4. Optimized library run-time (rearranging code and not using casting functor trick on compilers that accept local classes as template parameters). 5. Added BOOST_LOCAL_FUNCTION_NAME(inline ...) and BOOST_LOCAL_FUNCTION_NAME(recursive ...). 6. Added BOOST_LOCAL_TYPEOF. 7. Added bind(type) to specify bind type explicitly (skipping Boost.Typeof type deduction). 8. Removed boost::local::function (use boost::function instead). 9. Added boost::local::function::overload to overload local functions (and functors in general). 10. Implemented support for nesting local functions, blocks, and exits into one another. Boost.Local was used by Gregory Crosswhite in one of his project: https://github.com/gcross/CodeSearch -- Lorenzo

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