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

[gsoc] JSON?
by Rene Rivera 08 Apr '11

08 Apr '11

Students and other interested parties, I would love it if there was a Boost quality JSON data parser, and optional printer, library. Currently I use one based on Spirit1 which has many drawbacks. I've been waiting for someone in the Spirit team, i.e. Joel, to have some mythical free time and inclination to write such a thing. But I'd really love one sooner, rather than later. Having one that is good and based on the latest Spirit would be wonderful. I can't say I have the time to mentor such a project. Hence this is just a though ;-) -- -- Grafik - Don't Assume Anything -- Redshift Software, Inc. - http://redshift-software.com -- rrivera/acm.org (msn) - grafik/redshift-software.com -- 102708583/icq - grafikrobot/aim,yahoo,skype,efnet,gmail

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[GSoC] NLP Idea for GSoC 2011 project
by Sarma Tangirala 08 Apr '11

08 Apr '11

Hello list, I have worked with Boost on my projects but haven't really thought of using C++ as a language for NLP. The NLP that I have done is on Python and Java, for their built-in string methods. I don't know if this is inexperience or ignorance, but does C++ work well for NLP? I was thinking of having a GSoC project that is devoted to provide support for NLP. I mean like the kind that looks real easy on python. Also, I was looking at some C++ code using Boost/tokenizer.hpp that tokenized some text and it looked a bit scary. Any suggestions or advice? -- Regards, Sarma Tangirala, Junior - Class of 2012, Department of Information Science and Technology, College of Engineering Guindy - Anna University

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[con] Links to BoostCon2009, session material
by Joachim Faulhaber 08 Apr '11

08 Apr '11

Hi, I tried to refer to some session material from BoostCon2009 under the link where it was available once: http://www.boostcon.org/community/wiki/show/Start/HandsOnCXX0x/ This link is broken, so I searched the new conference site: http://boostcon.boost.org/ Unfortunately I didn't find it there either. Are those session materials available somewhere else? Thanks, Joachim -- Interval Container Library [Boost.Icl] http://www.joachim-faulhaber.de

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lp solver GSOC proposal
by Chad Seibert 08 Apr '11

08 Apr '11

Hi, Just letting the community know that a draft version of my lp solver GSOC proposal can be found here: http://www.google-melange.com/gsoc/proposal/review/google/gsoc2011/chadjsei… Any feedback would be greatly appreciated! Chad Seibert

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Re: [boost] [Boost-users] Writing large binary files with boost gzip
by Steven Watanabe 08 Apr '11

08 Apr '11

AMDG On 04/07/2011 05:39 PM, Anders Knudby wrote: > Many thanks for the quick response. And apologies for being a total newbie, > but how do I close the stream (and how do I check that it has been closed)? > With normal iostreams I would just write "out.close();", out being the name > of the stream. But that doesn't seem to be the way to do it for > filtering_iostreams?!? It should be closed when it goes out of scope or when you call pop. > And I would think it would close when it goes out of > scope, but I haven't checked. Yes, the stream is closed when it goes out of scope. > Any help appreciated. I'm pleased it worked > for you on Linux, but I'm largely stuck with Windows for the time being... > I can try it on Windows, but it'll take a little bit, as I don't have zlib installed, right now. In Christ, Steven Watanabe

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[phoenix] Functions and function pointers
by Lorenzo Caminiti 07 Apr '11

07 Apr '11

Hello all, How do I call functions and function pointers from within a Boost.Phoenix lambda function? For example: #include <boost/spirit/include/phoenix.hpp> #include <iostream> #include <vector> #include <algorithm> #include <cassert> #define N 1e4 #define S N * 1e2 const double& id(const double& x) { return x; } int main() { using boost::phoenix::ref; using boost::phoenix::arg_names::_1; double sum = 0.0; int factor = 1; const double& (*f)(const double&) = &id; std::vector<double> v(S); std::fill(v.begin(), v.end(), 1.0); for (size_t n = 0; n < N; ++n) { std::for_each(v.begin(), v.end(), ( ref(sum) += id(factor * f(_1)) // <<<<<<<<<<<<<< how do I call id(...) and f(...)? )); } std::cout << sum << std::endl; assert(sum == N * S); return 0; } Thank you very much. -- Lorenzo

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[optional] Incorrect example
by Ahmed Charles 07 Apr '11

07 Apr '11

http://www.boost.org/doc/libs/1_46_1/libs/optional/doc/html/boost_optional/… int x = 1 ; int& rx = x ; optional<int&> ora ; optional<int&> orb(x) ; ora = orb ; // now 'ora' is bound to 'x' through 'rx' *ora = 2 ; // Changes value of 'x' through ' ora'assert(x==2); Either the comment on the fifth line is wrong or the fourth line should construct from rx rather than x.

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[context] future design
by Oliver Kowalke 07 Apr '11

07 Apr '11

Hello, modifications I've made: - context: - stack unwinding: bool context::finished() const indicating that the called function has finished -> stack already unwinded boid context::unwind_stack() jump back into context and throw a special exception -> stack will be unwinded (requires that no try/catch(...) was used) - context is now moveable - is not a template == the stack type is only passed/known in the templated ctor - the function to be called by the context is not saved on top of the stack - exceptions replaced by assertions / exceptions.hpp removed - fcontext_t used as default implementation; ucontext_t only fallback for platforms not supported by fcontext_t - on Windows Win Fiber API is used as default - protected stack: - keyword explicit added to ctor - public static members min_stacksize, max_stacksize, default_stacksize - fcontext_t renamed to boost_fcontext_t, boost_fcontext_get(), boost_fcontext_set(), boost_fcontext_jump(), boost_fcontext_make() - i386 ASM preserves SSE2 control/status word - x86 ASM uses indirect jump for boost_fcontext_set() and boost_fcontext_jump() code is available at git://git.gitorious.org/boost-dev/boost-dev.git branch context-dev. @Vicente: could you check your SPAM filter , please (I've send several eMails to you). best regards, Oliver

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Re: [boost] [range] for_each and std::map of std::list
by Thorsten Ottosen 07 Apr '11

07 Apr '11

Den 07-04-2011 11:37, Mathias Gaunard skrev: > On 06/04/2011 19:55, Thorsten Ottosen wrote: >> I suggest the syntax >> >> rngOfContainers | boost::adaptors::flattened >> >> and the underlying iterator should be up to bidirectional (if the >> underlying two container types support it). >> >> Anyone interested in implementing this? > > I have an implementation of this somewhere. > > One annoying thing is that you cannot detect that a type is a range > reliably. Well, that is only a problem if you want to avoid manually applying the adaptor twice (or more), right? If so, I think that is a limitation we can live with. A simple solution covers most cases IMO. -Thorsten

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mismatched versions of Boost.Build engine and core
by Paul A. Bristow 07 Apr '11

07 Apr '11

I've got this message after running a bjam warning: mismatched versions of Boost.Build engine and core warning: Boost.Build engine (bjam) is 03.1.19 warning: Boost.Build core (at I:/boost-trunk/tools/build/v2) is 2011.04-svn Should I worry about this? I've tried to re-build using I:\boost-trunk\tools\build\v2\engine>bjam --toolset=msvc >build_bat.log but it still complains ### No toolset specified. Please use --toolset option. Is this supposed to be --toolset=msvc or --toolset msvc Suggestions? Thanks Paul PS This bit of the doc didn't seem right be me "For the Boost.Jam source included with the Boost distribution the jam source location is BOOST_ROOT/tools/jam/src." and was suggesting running build.bat I:\boost_1_46_0\tools\build\v2\engine\src contained build.bat and build.jam --- Paul A. Bristow, Prizet Farmhouse, Kendal LA8 8AB UK +44 1539 561830 07714330204 pbristow(a)hetp.u-net.com

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