April 2003 - Boost-users - lists.boost.org

Spirit - rule generating functions
by brockpeabody 06 Apr '03

06 Apr '03

Does anyone know the best way to return a rule from a function by value? I know that the following does not work, but what's the best workaround? struct calculator : grammar<calculator> { template <typename ScannerT> struct definition { definition(const calculator&) { r = make_complex_rule('A') | make_complex_rule('B'); } typedef rule<ScannerT> rule_type; rule_type const& start() { return r;} private: rule_type make_complex_rule(char c) { return c >> real_p; //boom } rule_type r; }; }; my current workaround is the following nastiness: //inside struct calculator::definition<> rule_type& anonymous_rule() { anonymous_rules.push_back( boost::shared_ptr<rule_type>(new rule_type)); return *anonymous_rules.back(); } rule_type& make_complex_rule(char c) { return anonymous_rule() = c >> real_p; } std::vector<boost::shared_ptr<rule_type> > anonymous_rules; Is there a better way? Also, I've got an easy one... Why is a grammar passed by const reference to its definition? Does Spirit make copies of the grammars internally? I ask because otherwise the grammar class seems like the ideal place to store state information (like numbers on a calculator's stack). Thanks ahead of time! Brock Peabody brock.peabody(a)npcinternational.com

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Tuple compatibility with VS.Net
by toddbfleming 06 Apr '03

06 Apr '03

I downloaded boost 1.30.0 but am having trouble with the Tuple library with Visial Studio.Net. The following code produces the errors: #include <boost/tuple/tuple.hpp> boost::tuple<int, int> f() { return boost::tuple<int, int>(1, 1); } c:\cpp\boost_1_30_0 \boost\tuple\detail\tuple_basic_no_partial_spec.hpp(411) : error C2039: 'map_tuple_to_cons' : is not a member of 'boost::detail' This code is: class tuple : public detail::map_tuple_to_cons<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>::cons1 This appears to be a compiler bug. The code at this line is in the boost::tuples namespace but the compiler seems to be ignoring boost::tuples::detail. I replaced detail with tuples::detail in many places in this code. Next error: c:\cpp\boost_1_30_0 \boost\tuple\detail\tuple_basic_no_partial_spec.hpp(456) : error C2629: unexpected 'boost::tuple<T1,T2,T3,T4,T5,T6,T7,T8,T9,T10> (' This code is: template<typename Head, typename Tail> explicit tuple(const cons<Head, Tail>& other) : cons1(other.head, other.tail) { } Visual C++ doesn't seem to understand template constructors. I replaced the template constructor with a copy constructor. VC++ failed to create the default copy constructor :( c:\cpp\boost_1_30_0 \boost\tuple\detail\tuple_basic_no_partial_spec.hpp(470) : error C2143: syntax error : missing ',' before '<' The code is: template<typename Head, typename Tail> self_type& operator=(const cons<Head, Tail>& other) Lookup failed on cons. I added tuples:: prefix. Has anyone else run into these or might I have a configuration problem? Thanks! Todd Fleming

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documentation
by luise_mang 05 Apr '03

05 Apr '03

Hello, Is there some centralized documentation for offline-studies available (PDF, some platform-specific help docs, whatever - just download once, view offline many) ? thanx, Luise

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RE: [Boost-Users] Please, please help!!!
by scleary＠jerviswebb.com 05 Apr '03

05 Apr '03

Your error message indicates that exceptions are disabled. Try not disabling them. I think some versions of GCC might disable exceptions by default based on the language its compiling for -- e.g., if it's invoked as 'gcc' or the filename extension designates a C file. I didn't see this behaviour under Cygwin, though. I can get it to compile under Cygwin just by adding the Boost include with -I and defining __linux__ with -D. HTH, -Steve > -----Original Message----- > From: Jon Agiato [mailto:JonAgiato@nyc.rr.com] > Sent: Friday, April 04, 2003 11:56 AM > To: Boost-Users(a)yahoogroups.com > Subject: RE: [Boost-Users] Please, please help!!! > > > Hi Steve, > Thanks again for the help. I did that and now the > file is recognized, but I am receiving the following > error upon compilation: > > In file included from main.cpp:3: > /usr/include/c++/3.2/boost/libs/random/random_device.cpp: > In member function > `void boost::random_device::impl::error(const > std::string&)': > /usr/include/c++/3.2/boost/libs/random/random_device.cpp:92: > exception handling > disabled, use -fexceptions to enable > gmake: *** [main.o] Error 1 > > The program is the same except now I am including > #include <boost/libs/random/random_device.cpp>. > > Thanks again! > > Jon Agiato > JonAgiato(a)nyc.rr.com > > --- Jon Agiato <jonagiato(a)nyc.rr.com> wrote: > > >> > >> ----- Original Message ----- > >> From: scleary(a)jerviswebb.com > >> To: Boost-Users(a)yahoogroups.com > >> Sent: Friday, April 04, 2003 10:49 AM > >> Subject: RE: [Boost-Users] Please, please help!!! > >> boost::random_device > >> > >> > >> There is a source file under the libs/random > >> directory that contains the > >> implementation of random_device. You'll have to > >> include it in your project > >> in order to link. > >> > >> -Steve > >> > > > > > >>> > -----Original Message----- > >>> > From: Jon Agiato [mailto:JonAgiato@nyc.rr.com] > >>> > Sent: Thursday, April 03, 2003 10:02 PM > >>> > To: Boost-Users(a)yahoogroups.com > >>> > Subject: [Boost-Users] Please, please help!!! > >> > >> > >> boost::random_device > > > > > >>> > > >>> > > >>> > Hello all, > >>> > > >>> > I am attempting to use the non-deterministic > >> > >> > >> random number generator > > > > > >>> > class contined in boost::random and have > >> > >> > >> encountered the following > > > > > >>> > errors upon running the program. The program does > >> > >> > >> compile without > > > > > >>> > errors, and I am using KDevelop 2.1.3 in the > >> > >> > >> RedHat Linux 8.0 > > > > > >>> > environment. > >>> > > >>> > Here's the offending code: > >>> > > >>> > #include <iostream> > >>> > #include <cstdlib> > >>> > #include <boost/nondet_random.hpp> > >>> > > >>> > int main() > >>> > { > >>> > boost::random_device dev; > >>> > > >>> > return EXIT_SUCCESS; > >>> > } > >>> > > >>> > I receive the following error message: > >>> > /home/JAgiato/boosttest/boosttest/main.cpp:6: > >> > >> > >> undefined reference to > > > > > >>> > `boost::random_device::default_token' > >>> > /home/JAgiato/boosttest/boosttest/main.cpp:6: > >> > >> > >> undefined reference to > > > > > >>> > > >> > >> > >> > > > > > `boost::random_device::random_device[in-charge](std::basic_str > > >> > ing<char, > >> > std::char_traits<char>, std::allocator<char> > > > > > > > const&)' > > >> > /home/JAgiato/boosttest/boosttest/main.cpp:8: > > > > > > undefined reference to > > >> > `boost::random_device::~random_device > > > > > > [in-charge]()' > > >> > > >> > My goal is to use this class to produce > > > > > > non-deterministic 32 bit > > >> > integers which will be streamed to a binary file. > > > > > > Any help is greatly > > > > apprechiated! Thank you! > > > > > > Jon Agiato > > > JonAgiato(a)nyc.rr.com > > > > ------------------------ Yahoo! Groups Sponsor > ---------------------~--> > Get 128 Bit SSL Encryption! > http://us.click.yahoo.com/xaxhjB/hdqFAA/VygGAA/EbFolB/TM > -------------------------------------------------------------- > -------~-> > > Info: <http://www.boost.org> > Wiki: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl> > Unsubscribe: <mailto:boost-users-unsubscribe@yahoogroups.com> > > > Your use of Yahoo! Groups is subject to > http://docs.yahoo.com/info/terms/ > >

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Extending max. arity of tuples
by Max Motovilov 05 Apr '03

05 Apr '03

I ran against the arity limitation of 10 and to resolve it, modified tuple_basic.hpp to use the preprocessor package for all variable length argument lists (with macro BOOST_TUPLE_MAX_ARITY serving as a single parameter configurable from config/user.hpp). I'm not sure if this modification will be of general interest, but if so, where do I send it? Modified code has been tested with MSVC 2003 (7.1). Regards, ...Max...

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problems building boost thread with Linux7.2
by ZYA 04 Apr '03

04 Apr '03

Dear, How to build boost thread libs step by step? zya! Info: <http://www.boost.org> Wiki: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl> Unsubscribe: <mailto:boost-users-unsubscribe@yahoogroups.com> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ [Non-text portions of this message have been removed]

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RE: [Boost-Users] problems building boost thread with Linux7.2
by Jim.Hyslop 04 Apr '03

04 Apr '03

ZYA [mailto:Zhao.Yan@inventec.com] wrote: > How to build boost thread libs step by step? Have a look at these pages: http://www.boost.org/tools/build/index.html http://www.boost.org/libs/thread/doc/build.html The first page gives a fairly detailed set of instructions on building bjam, the tool which is used to build the thread library (and other Boost libraries). The second page tells you how to use bjam to build the library itself. If these pages don't help, feel free to post any additional questions (and I promise to read the subject line as well :=) -- Jim

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Re: [Boost-Users] Re: Understanding MPL
by Tanton Gibbs 04 Apr '03

04 Apr '03

"Paul Mensonides" <yg-boost-users(a)m.gmane.org> wrote in message news:b6ifnh$5l0$1@main.gmane.org... > Edward Diener wrote: > > >> What specifically would you have me do? The pp-lib docs do not > >> attempt to explain the implementation of the pp-lib itself. > > > > I don't want an explanation of the inner workings of the pp-lib. I > > would like to see an explanation of the pp-lib which attempts to > > explain the functionality of it from the user's point of view. > > Something like a grouping of the macros in it from the point of view > > of general areas of functionality, with the specific macros grouped > > and explained within each area. It honestly sounds to me like Edward wants a tutorial -- something that the PP library does not currently have. I have used the PP lib numerous times for many different types of problems, and have always come away with a good feeling towards the docs. They are easy to navigate and are structured in such a way that you can find what you are looking for quickly. However, I also understand Edward's point about a tutorial. If I had not come to the PP lib with a particular problem, but instead just wanted to get a "warm, fuzzy" feeling about it, then it would be natural to want a tutorial to walk me through each macro giving an actual program and describing why each macro used in the program was chosen as well as what it expands to. I realize that this would be a huge undertaking, but perhaps there are people out there like myself, who have used and enjoy the PP lib that would help you in this endeavor if you choose to undertake it. I definately think it would be worthwhile to have a tutorial to help the unitiated get their feet wet. Basically, give them a problem to solve, show them how to solve it, then describe in detail how the solution was derived. The tutorial would then not get in the way of the initiated, but would bring the uninitiated up to speed. Thanks! Tanton [Non-text portions of this message have been removed]

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boost::lexical_cast extension for boost::any ...
by Electric Monk 04 Apr '03

04 Apr '03

I have a need to cast a boost::any with an arbitrary contained type to another type, using a boost::lexical_cast for example. Consider the following: #include <boost/any.hpp> class obj { public: int val0; double val1; void setval(int i, boost:any const & val) { switch (i) { case 0: val0 = boost::any_cast<int>(val); break; case 1: val1 = boost::any_cast<double>(val); break; } } }; int main(int, char*[]) { obj o; o.setval(0, 1); o.setval(1, 2); return 0; } As expected, this throws a boost::bad_any_cast() at runtime. I'd like to write code similar to (from obj::setval above): case 0: val0 = boost::lexical_cast<int>(val); break; case 1: val1 = boost::lexical_cast<double>(val); break; Unfortunately boost::lexical_cast doesn't handle a parameter of type boost::any, since there isn't an overload of 'std::ostream operator <<()' for type boost::any. Can anyone suggest a simple way around this? My own musings on the subject have lead me to thinking that there needs to be a simple way to extract the contained value, or write it to a stream, without knowing its type. The simplest method I can see would be to add a function to boost::any::placeholder which either returns a string representation of the held value or writes the held value to a std::basic_ostream. This should allow a simple boost::lexical_cast conversion for boost::any to any arbitrary type. Comments? Have I missed anything major? Oh, and yes, I know that this goes beyond the intent of boost::any. I could easily create my own variant of boost::any which acts in the way I want, but I think this kind of functionality is useful in a number of cases, so it'd be nice to have the best solution possible... which is best discussed by the people here, who are much better versed in the boost library than I :) -- Corey Murtagh The Electric Monk "Quidquid latine dictum sit, altum viditur!"

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RE: [Boost-Users] problems building boost thread with Linux7.2
by Jim.Hyslop 04 Apr '03

04 Apr '03

I wrote: > ZYA [mailto:Zhao.Yan@inventec.com] wrote: > > Dear, > > How to build boost thread libs step by step? > Step 1: tell us which compiler and platform you are using. My apologies, I didn't read the subject line. I use Windows, so I can't help. -- Jim

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