- Boost-users - lists.boost.org

Re: [Boost-users] [Proto] Extracting types of sub-expression in transform
by Ivan Godard 19 Oct '08

19 Oct '08

Eric Niebler wrote: Joel Falcou wrote: > > Hello, > > > > i have a DSL where terminal are defined like : terminal< simd<proto::_> > > > What I want is that any binary operator that apply on those terminal should > > be available only if both lhs and rhs parts have the same underlying > > type. E.G : > > > > simd<float> + simd<float> is ok while > > (simd<char> + simd<char>)*simd<float> is not ok. > > > > How I can enforce this check ? Is having a transform that take an > > expression and returns > > the underlying type OR mpl::void_ if an error occurs the good solution ? > This question has come up a couple of times. The solution isn't very pretty ... write a grammar that allows expressions with incompatible terminals, and then write a separate transform that checks the terminals for compatibility. This issue came up during Proto's review and I posted some example code here (see the SameTerminals transform): http://lists.boost.org/Archives/boost/2008/03/135169.php I wish I knew of a better solution. The canonical way to incorporate typing (including much richer type systems than this) in a formal grammar is through van Wijngaarden grammars. See http://en.wikipedia.org/wiki/Algol68. It is possible to generate both the parser and type analysis from such a grammar, and compilers that do so still exist. Sadly, there is no Boost VWG library. Perhaps you'll write one?

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[thread_safe_signals][signals2] review Nov 1st - Nov 10th
by Stjepan Rajko 19 Oct '08

19 Oct '08

Just a brief note: Thanks to the 5 reviewers that have signed up to review the Signals2 library (formerly known as thread_safe_signals) submitted by Frank Mori Hess, the review will happen as planned: November 1st - November 10th. Many thanks to the committed reviewers, and I hope other interested boosters that find some free time during the review period will be joining us as well. Kind regards, Stjepan

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Apple iPod uses Boost
by Alexander Gutenev 19 Oct '08

19 Oct '08

Apple iPod uses Boost. At least looks like that.There's 'legal' in menu, where some software licenses are listed, the last one is Boost Software License. This may help someone to convince boss that Boost libraries are needed for any project, as they are used even in such tiny and useless thing ;-)

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Where is the numeric/bindings package?
by Peng Yu 19 Oct '08

19 Oct '08

Hi, I can not find the numeric/bindings package in boost 1.36.0. Can somebody let me know where it is? Thanks, Peng

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Re: [Boost-users] Apple iPod uses Boost
by Robert Marion 18 Oct '08

18 Oct '08

> From: Gennaro Prota > Subject: Re: [Boost-users] Apple iPod uses Boost > > Well, of course Boost isn't the only library using the Boost > Software License. And, are they distributing the sources? > Otherwise I don't see why reproducing the license. I haven't seen the Boost License being used outside of Boost, although certainly the license can be applied to any open source software. Since the Boost license is similar to the BSD style license, it is likely that an open source project would choose one of the more popular BSD or MIT style licenses. Also, the Boost license does not require that source be available for distribution. That is a characteristic of GPL, LGPL and other copyleft licenses. The Boost license is an attribution license. See http://www.boost.org/users/license.html. ________________________________ Robert Marion http://www.palamida.com

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Must cast unsigned int for random generator seed
by Phillip Jones 18 Oct '08

18 Oct '08

I wanted to save the initial state of a random number generator and I ran into this issue - boost::mt19937 rng; unsigned int rseed = static_cast<unsigned int>(std::time(0)); //rng.seed( rseed ); // This causes an error rng.seed( static_cast<unsigned int>(rseed) ); // ok The error is "mersenne_twister.hpp:103: error: `gen' cannot be used as a function". Obviously not a big problem since I can just use the cast and keep going. But is there a reason for this behavior? It seems odd that one must cast an unsigned int as an unsigned int to make it work.

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[Proto] Extracting types of sub-expression in transform
by Joel Falcou 18 Oct '08

18 Oct '08

Hello, i have a DSL where terminal are defined like : terminal< simd<proto::_> > What I want is that any binary operator that apply on those terminal should be available only if both lhs and rhs parts have the same underlying type. E.G : simd<float> + simd<float> is ok while (simd<char> + simd<char>)*simd<float> is not ok. How I can enforce this check ? Is having a transform that take an expression and returns the underlying type OR mpl::void_ if an error occurs the good solution ? Thanks in advance -- ___________________________________________ Joel Falcou - Assistant Professor PARALL Team - LRI - Universite Paris Sud XI Tel : (+33)1 69 15 66 35

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Re: [Boost-users] return type of boost::iostreams::stream<T>::read()
by Struebing, Axel, le-tex 18 Oct '08

18 Oct '08

okay, it's within my grasp now. Primarily I get a basic_istream. To facilitate the 'while std::cin' idiom, there is a conversion of basic_istream to void* defined. That seems to hit me in my example. FYI: std::streamsize i = istr.read(buffer,10); is calling the read-function of my DeviceT template parameter, perfect. So I am probably going to use a read + gcount-combination. Thanks again Axel > Hallo Éric, > > although it is not an exact fit it will be of value in evaluating my > options. > > kind regards > Axel Strübing > > > > Reading the documentation about boost::iostreams library I could not > > > find the information which return type the boost::iostreams::stream's > > > class is giving me calling read(). > > > > > >From the documentation, a boost::iostreams::stream derives from an > > > std::basic_[i|o]stream, depending on the model of its underlying > > > Device. In your example, the device is a Source, so I guess that the > > > stream derives from std::basic_istream, whose read(char*, streamsize) > > > method returns a basic_istream, not a streamsize. > > > > The library offers the "streamsize read(stream, char*, streamsize)" > > function template. Using it in your example yould give something like > > (not tested): > > > > #include <boost/iostreams/stream.hpp> > > #include <boost/iostreams/device/file.hpp> > > #include <boost/iostreams/operations.hpp> > > > > int main(void){ > > namespace bio = boost::iostreams; > > bio::stream<bio::file_source> istr(std::string("in.pdf")); > > char buffer[10]; > > std::streamsize i = bio::read(istr,buffer,10); > > return 0; > > } > > > > > > HTH, > > > > Éric Malenfant > > --------------------------------------------- > > Two wrongs don't make a right but three rights make a left. > > --

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nested template tests using boost.test BOOST_AUTO_TEST_CASE_TEMPLATE
by johanngoetz 18 Oct '08

18 Oct '08

It seems that one cannot do nested AUTO_TEST_CASE_TEMPLATE's with boost.test. Is there another way around this (besides unrolling manually)? I wish to do something like the following: i.e. testing every combination of two (or more?) lists of types. Example below. Thank you, Johann. define BOOST_TEST_MODULE std_map #define BOOST_TEST_DYN_LINK #include <map> #include <boost/test/unit_test.hpp> #include <boost/test/test_case_template.hpp> #include <boost/mpl/list.hpp> typedef boost::mpl::list<short, int, long, long long> test_int_types; typedef boost::mpl::list<float, double, long double> test_float_types; BOOST_AUTO_TEST_SUITE( std_map_suite ) BOOST_AUTO_TEST_CASE_TEMPLATE( int_template_case, Ti, test_int_types ) { BOOST_AUTO_TEST_CASE_TEMPLATE( float_template_case, Tf, test_float_types ) { std::map<Ti, Tf> m; m.insert(std::make_pair((Ti)0,(Tf)0)); BOOST_CHECK_EQUAL(m.size(), size_t(1)); } } BOOST_AUTO_TEST_SUITE_END() -- View this message in context: http://www.nabble.com/nested-template-tests-using-boost.test-BOOST_AUTO_TES… Sent from the Boost - Users mailing list archive at Nabble.com.

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Using boost.signals with boost.bind
by Sergey Kishchenko 18 Oct '08

18 Oct '08

Hi, I have one problem with boost.bind and boost.signals I can't understand. Source code is the best description, therefore #include <iostream> #include <boost/signals.hpp> #include <boost/shared_ptr.hpp> #include <boost/bind.hpp> class Func : public boost::noncopyable { public: void operator()(int i) { std::cout<<"Func::operator("<< i <<")\n"; } }; typedef boost::signal<void ()> signal_type; Func f; signal_type::slot_type binded_func = boost::bind<void>(boost::ref(f),42); int main() { boost::shared_ptr<signal_type> apSig(new signal_type()); apSig->connect(binded_func); (*apSig)(); apSig.reset(new signal_type()); boost::signals::connection con = apSig->connect(binded_func); std::cout<<"Connected: "<<con.connected()<<" Blocked: "<<con.blocked()<<"\n"; } Program output: Func::operator(42) Connected: 0 Blocked: 1 Ie, if i create new signal and then try to connect to the same slot, it fails. If I use not boost::bind object but only boost::function as slot, all works ok. I can not understand, why? I used Boost 1.34.1, gcc 4.1.2 Regards, Sergey Kishchenko

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