April 2010 - Boost-users - lists.preview.boost.org

[GIL] Important fix
by Eloi Du Bois 22 Apr '10

22 Apr '10

I Christian and Lubomir, I am wondering if the two patchs I have made (which correct an important bug) will be on the boost_1.43 version. There is only a couple of lines to correct, but they are really important. I really hope you can do so, because it is critical for me (and other people who wants to work with exotic views). Thank you in advance, Eloi.

1 0

Spirit Newbie (balanced parentheses)
by EricB 21 Apr '10

21 Apr '10

Hi all I'm trying to use spirit in order to make a parser for a simple language. Last time i had to do this I was in school (some more than 15 years ago). I managed to do something that works but it does not handle "balanced parentheses". I know this is a common problem but after having look for every possible way of spelling "balanced parentheses" I did not find anything (that I could understand). The files I want to parse are made of ASCII char. They can contains commands that should be interpreted (replacement). Commands always start with "^!" (command switch). An example of a file content: text text text ^!for-each( A )( B ) text text text text I want to send the "text" strings to the std::cout and detect the commands "^!for-each( A )( B )" in order to process them. At the moment I only have one command "for-each" Where: A : is a query that can contain /'" and balanced () B : is the text to be sent to output for each result of the query. This can be a 'script' meaning text + commands, for example: aa bb ^!for-each(C)(D) tt yy uu therefore B can also contain balanced (). The rules, I wrote does not handled balanced () very well. For example the following command should be parsed successfully: ^!for-each( a/b/c()/e[]/d ) ( item [name] do ^!for-each(sub/text()) ( print() ) ) I need some advices. Thank you So here are my rules { boost::spirit::chlit<> LPAREN('('); boost::spirit::chlit<> RPAREN(')'); boost::spirit::strlit<> CMDSWITCH("^!"); script // main rule = * ( (boost::spirit::anychar_p - CMDSWITCH) | command ); command = boost::spirit::discard_first_node_d[ CMDSWITCH >> (for_each | boost::spirit::eps_p // for error reporting ) ]; for_each = boost::spirit::discard_first_node_d[ boost::spirit::as_lower_d["for-each"] >> *boost::spirit::space_p >> query >> *boost::spirit::space_p >> subscript ]; query = boost::spirit::inner_node_d[ LPAREN >> *(boost::spirit::anychar_p - ( RPAREN )) >> RPAREN ]; subscript = boost::spirit::inner_node_d[ LPAREN >> *( (boost::spirit::anychar_p - ( CMDSWITCH | RPAREN )) |command ) >> RPAREN ]; }

4 12

Re: [Boost-users] still stuck on expectation points
by Overmind DL1 21 Apr '10

21 Apr '10

-----Original Message----- From: philip tucker <phhht(a)earthlink.net> Sent: Tuesday, April 20, 2010 4:44 PM To: boost-users(a)lists.boost.org <boost-users(a)lists.boost.org> Subject: Re: [Boost-users] still stuck on expectation points On 16 Apr 2010, at 6:52 PM, OvermindDL1 wrote: > On Fri, Apr 16, 2010 at 7:47 PM, philip tucker > <phhht(a)earthlink.net> wrote: > >> >> On 16 Apr 2010, at 6:16 PM, OvermindDL1 wrote: >> >> >>> >>> start %= (constitkind >> (id > ':' > id) >> probs) % ","; >>> >>> >> >> Thanks, but I already tried it. Doesn't compile. >> > > Er, if you re-read my post I was saying *not* to do that, because that > will not work, that is actually what the compiler is doing because of > operator precedence. You should memorize the precedence rules for > C++, *especially* if you are going to be dealing with heavily > templated operator libraries like Spirit. > http://en.wikipedia.org/wiki/Operators_in_C_and_C%2B%2B > > Because you are mixing right-shifts (>>) and greater-than's (>), the > precedence causes them to collapse in different ways, which is why you > need the parenthesis like this: > start %= (constitkind >> (id > (':' > (id >> probs)))) % ","; > > Again, learn the C++ operator precedence rules and all this will make > easy sense. :) > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users If I have understood your advice correctly, you suggest that this code should compile: > start %= (constitkind >> (id > (':' > (id >> probs)))) % ","; It doesn't. _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users ____________________________________________________________ Sorry for the bad way to respond, on phone with outlook mobile. Do you have a complete compilable example that demonstrates your problem? Also, try asking on the Spirit mailing list.

3 2

Boost Bind Library
by Abhilash K 21 Apr '10

21 Apr '10

Is Boost Bind a library and is avaialable as a shared lib while building boost using bjam? If not, which shared lib contains Bind?

2 1

puzzle with enable_if
by John Dlugosz 21 Apr '10

21 Apr '10

I'm using the Microsoft 2008 compiler. The template template <typename T, typename D> struct is_proper_TD_types : std::tr1::integral_constant<bool, is_Universal_time_API<T>::value && (std::tr1::is_same<typename T::duration_t,D>::value || std::tr1::is_same<duration,D>::value || std::tr1::is_same<linear_duration,D>::value || is_dimensional_time<D>::value) > {}; gives an error "'T': must be a class or namespace when followed by '::'" when T is int. This kind of thing is mentioned in the enable_if documentation as the motivation for the "lazy" forms, because the compiler doesn't apply SFINAE for other templates. But, riddle me this: I created that line as an attempt to refactor the following, which DOES work OK: template <typename T, typename D> typename boost::enable_if_c< is_Universal_time_API<T>::value && (std::tr1::is_same<typename T::duration_t,D>::value || std::tr1::is_same<duration,D>::value || std::tr1::is_same<linear_duration,D>::value || is_dimensional_time<D>::value) ,T>::type operator+ (const T& t1, const D& d1) { // blah blah Basically, I just copied the bulk of the first argument of enable_if_c in the second listing to make a named metaprogramming predicate that I could use in several places. I don't see anything in your implementation of enable_if_c that would cause it to work: the argument is a template bool constant in both cases. Why does the bottom one work, when the top one doesn't? --John TradeStation Group, Inc. is a publicly-traded holding company (NASDAQ GS: TRAD) of three operating subsidiaries, TradeStation Securities, Inc. (Member NYSE, FINRA, SIPC and NFA), TradeStation Technologies, Inc., a trading software and subscription company, and TradeStation Europe Limited, a United Kingdom, FSA-authorized introducing brokerage firm. None of these companies provides trading or investment advice, recommendations or endorsements of any kind. The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any computer.

3 9

serialization of unordered_map
by Igor Filippov 21 Apr '10

21 Apr '10

Answering my own question - I was able to figure it out last night. Thank you for the wonderful library! Igor

2 3

[date_time] Formating overall lacking in flexibility & functionality?
by Sebastian Karlsson 21 Apr '10

21 Apr '10

Sorry for being a bit of a douche, but I find the formatting options in date_time lacking and would like to see what others think. We have a use case that I think displays some of the shortcomings. We have a time duration stored as an int representing the number of miliseconds. When displaying the time duration we want to use MM:SS,FFF, padding with 0s in order to get them to line up nicely. First problem here is it's not possible to control the number of fractions, we use substr to remove the last 3 unwanted digits, this however naturally doesn't respect rounding. The second problem is that it doesn't seem to be possible to control the padding, ( although this isn't a problem for our use case ). Another problem is that it doesn't seem to be possible to format a time_duration directly, the only solution which I've been able to find is to construct an arbitrary valid date and keep the time part at zero. This seems both unnecessary and imposes restrictions if one were interested in actually measuring and format long durations of time. I also think formatting a date time is often unnecessary verbose. I would personally appreciate formatting functionality along the lines of: // Apply formating_string to duration using supplied locale std::string format_time_duration( const boost::posix_time::time_duration& duration, const std::string& formating_string, const std::locale& locale = std::locale::classic() ); For reference, this is how we format our times: std::string format_highscore( unsigned int miliseconds ) { boost::posix_time::time_duration td = boost::posix_time::milliseconds( 10004 ); boost::posix_time::ptime pt( ( boost::gregorian::date( 2000, 1, 1 ) ) ); pt += td; std::stringstream ss; boost::posix_time::time_facet* df( new boost::posix_time::time_facet( "%M:%S,%f" ) ); ss.imbue( std::locale( ss.getloc(), df ) ); ss << pt; std::string ret = ss.str(); ret = ret.substr( 0, ret.size() - 3 ); return ret; }

1 0

[boost] [iostreams] Pipelined reference_wrappers of filters/device
by feverzsj 21 Apr '10

21 Apr '10

hi all, BOOST_IOSTREAMS_PIPABLE generate something like : template<..., typename component> pipeline<...> operator|(your_filter const& , component const&); It is proper for plan use, e.g. filter1 | filter2 | ... | device. But for boost::reference_wrapper, ref(filter1) | ref(filter2) |...|ref(device), after type conversion, will be : filter1 | ref(filter2) |...|ref(device), which may confuse the user. So, will it be a good idea to make another reloaded operator|(reference_wrapper<your_filter> const&, component const&)) ? I have written a macro to handle this( simply copy and modify BOOST_IOSTREAMS_PIPABLE): #define BOOST_IOSTREAMS_EXTENDED_PIPABLE(filter, arity) \ template< BOOST_PP_ENUM_PARAMS(arity, typename T) \ BOOST_PP_COMMA_IF(arity) typename Component> \ ::boost::iostreams::pipeline< \ ::boost::iostreams::detail::pipeline_segment<filter BOOST_IOSTREAMS_TEMPLATE_ARGS(arity, T)> \ ,Component \ > \ operator|(const filter BOOST_IOSTREAMS_TEMPLATE_ARGS(arity, T)& f, const Component& c) \ { \ typedef \ ::boost::iostreams::detail::pipeline_segment< \ filter BOOST_IOSTREAMS_TEMPLATE_ARGS(arity, T) \ > segment; \ return ::boost::iostreams::pipeline<segment, Component> \ (segment(f), c); \ } \ template<BOOST_PP_ENUM_PARAMS(arity, typename T) \ BOOST_PP_COMMA_IF(arity)typename Component> \ ::boost::iostreams::pipeline< \ ::boost::iostreams::detail::pipeline_segment< \ boost::reference_wrapper<filter BOOST_IOSTREAMS_TEMPLATE_ARGS(arity, T)> > \ ,Component \ > \ operator|(const boost::reference_wrapper<filter BOOST_IOSTREAMS_TEMPLATE_ARGS(arity, T)>& wf \ ,const Component& c) \ { \ typedef \ ::boost::iostreams::detail::pipeline_segment< \ boost::reference_wrapper<filter BOOST_IOSTREAMS_TEMPLATE_ARGS(arity, T)> \ > segment; \ return ::boost::iostreams::pipeline<segment, Component>(segment(wf), c); \ } \ /**/ -- View this message in context: http://old.nabble.com/-boost---iostreams--Pipelined-reference_wrappers-of-f… Sent from the Boost - Users mailing list archive at Nabble.com.

1 0

[Boost MPI] : Point to Point Communication
by Pooja Varshneya 21 Apr '10

21 Apr '10

Hi Everyone, I am trying to send a user-defined structure named ABC using boost::mpi::send () call. The given struct contains a vector "data" whose size is determined at runtime. Objects of struct ABC are sent by master to slaves. But the slaves need to know the size of vector "data" so that the sufficient buffer is available on the slave to receive this data. I can work around it by sending the size first and initialize sufficient buffer on the slave before receiving the objects of struct ABC. But that defeats the whole purpose of using STL containers. Does anyone know of a better way to do handle this ? Any suggestions are greatly appreciated. Here is a sample code that describes the intent of my program. This code fails at runtime due to above mentioned reason. struct ABC { double cur_stock_price; double strike_price; double risk_free_rate; double option_price; std::vector <char> data; }; namespace boost { namespace serialization { template<class Archive> void serialize (Archive &ar, struct ABC &abc, unsigned int version) { ar & abc.cur_stock_price; ar & abc.strike_price; ar & abc.risk_free_rate; ar & abc.option_price; ar & bopr.data; } } } BOOST_IS_MPI_DATATYPE (ABC); int main(int argc, char* argv[]) { mpi::environment env (argc, argv); mpi::communicator world; if (world.rank () == 0) { ABC abc_obj; abc.cur_stock_price = 1.0; abc.strike_price = 5.0; abc.risk_free_rate = 2.5; abc.option_price = 3.0; abc_obj.data.push_back ('a'); abc_obj.data.push_back ('b'); world.send ( 1, ANY_TAG, abc_obj;); std::cout << "Rank 0 OK!" << std::endl; } else if (world.rank () == 1) { ABC abc_obj; // Fails here because abc_obj is not big enough world.recv (0,ANY_TAG, abc_obj;); std::cout << "Rank 1 OK!" << std::endl; for (int i = 0; i < abc_obj;.data.size(); i++) std::cout << i << "=" << abc_obj.data[i] << std::endl; } MPI_Finalize(); return 0; } Thanks, Pooja

1 0

Who can give me a sample for how to using boost::thread in a MFC regular dll?
by DDGG 21 Apr '10

21 Apr '10

Hello everyone! I have a MFC application that using boost::thread, it runs well. Now I wrapped it to a MFC regular dll, but I get a assertion error when I using this dll. // (In my another MFC dialog application) void AFXAPI AfxCoreInitModule() { ASSERT(AfxGetModuleState() != AfxGetAppModuleState()); // assertion error // the return value of AfxGetModuleState() and AfxGetAppModuleState() are both not-empty, // but they are different. ... } Any advice? thanks!

3 5