- Boost-users - lists.boost.org

[Proto] proto::reverse_fold_tree
by Kim Kuen Tang 02 Feb '09

02 Feb '09

Hi all, i want to use the function proto::reverse_fold_tree to build a heterogeneous list from the expression "((a*b+c)*d+e)*f". The resulting sequence only contains the two terminals 'a' and b'. So i am a little bit confused. But using the function proto::fold_tree it produces correctly the sequence [f,e,d,c,b,a]. (Btw the two functions proto::fold_tree and proto::fold produce the same sequence [f,e,d,c,b,a], what is their difference? ) Here is the code: #include <iostream> #include <boost/proto/proto.hpp> #include <boost/proto/proto_typeof.hpp> #include <boost/fusion/container.hpp> #include <boost/fusion/algorithm/iteration.hpp> #include <boost/fusion/include/iteration.hpp> #include <boost/typeof/typeof.hpp> namespace mpl = boost::mpl; namespace proto = boost::proto; namespace fusion = boost::fusion; using proto::_; proto::terminal<char>::type const a = {'a'}; proto::terminal<char>::type const b = {'b'}; proto::terminal<char>::type const c = {'c'}; proto::terminal<char>::type const d = {'d'}; proto::terminal<char>::type const e = {'e'}; proto::terminal<char>::type const f = {'f'}; struct FoldToList : proto::or_< proto::when<proto::terminal<_>,fusion::cons<proto::_value, proto::_state>(proto::_value, proto::_state) > ,proto::when<proto::nary_expr<_,proto::vararg<_> >, proto::fold_tree<proto::_,fusion::nil(),FoldToList > > > {}; struct FoldToListReverse : proto::or_< proto::when<proto::terminal<_>,fusion::cons<proto::_value, proto::_state>(proto::_value, proto::_state) > ,proto::when<proto::nary_expr<_,proto::vararg<_> >, proto::reverse_fold_tree<proto::_,fusion::nil(),FoldToListReverse > > > {}; struct print { typedef void result_type; template<class T> result_type operator()(T const& t) const { std::cout<<t<<"\t"; } }; int main() { BOOST_PROTO_AUTO(expr, ((a*b+c)*d+e)*f ); proto::display_expr(expr); BOOST_MPL_ASSERT(( proto::matches<BOOST_TYPEOF(expr), FoldToList>)); BOOST_MPL_ASSERT(( proto::matches<BOOST_TYPEOF(expr), FoldToListReverse>)); BOOST_AUTO(sequence1,FoldToList()(expr)); fusion::for_each(sequence1,print()); std::cout << "\n--------------------\n"; BOOST_AUTO(sequence2,FoldToListReverse()(expr)); fusion::for_each(sequence2,print()); std::cout << "\n--------------------\n"; } Cheers Kim Tang

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[boost.filesystem] query
by Sean Farrow 02 Feb '09

02 Feb '09

Hi: I am using boost.filesystem to hold a path including filename. would the function stem() of the path object give me the path excluding the filename? If i have: c:\program files\boost\welcome.txt The output wanted is: c:\program files\ Any help apreciated. Sean.

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using boost.foreach with boost.array
by Sean Farrow 02 Feb '09

02 Feb '09

Hi: is it possible to use boost.foreach with boost.array? Cheers Sean.

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Generate automatically an enum inside a template regarding to parameter
by Hansi 02 Feb '09

02 Feb '09

Hi, Is there a way to generate automatically an enum inside an template. I have e.g. the following template: template<int nr> class Test { enum { R1, ... Rx // where x is equal to nr }; } Thanks for any hint! Regards Hansjörg

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Preprocessor to generate enum
by Hansi 02 Feb '09

02 Feb '09

Hi, what is the best way to generate the following enum with the preprocessor library (boost 1.34.1)? enum { R1=0, R2=1, ... }; Best regards Hansjörg

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Re: [Boost-users] Compiler Error With boost::bind and boost::signals
by KERSAM 02 Feb '09

02 Feb '09

I forgot: I am using the Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 14.00.50727.762 for 80x86 and Boost Version 1.35. KERSAM wrote: > > Hello. > > I have a compiler error when I try to use boost::bind and boost::signals. > Here is the code: > > -------------------- > #include<boost/bind.hpp> > #include<boost/signals.hpp> > > class MyBoostTest { > public: > void testFunction(int x, int y) {} > }; > > > void doConnect() { > boost::signal2<void, int, int> signal; > signal.connect(boost::bind<void>(&MyBoostTest::testFunction, new > MyBoostTest, _1)); > } > ----------------------------------- > > The compiler gives me the following error: > c:\3rdparty\boost\boost\bind.hpp(289) : error C2064: term does not > evaluate to a function taking 2 arguments > class does not define an 'operator()' or a user defined conversion > operator to a pointer-to-function or reference-to-function that takes > appropriate number of arguments > > What am I doing wrong? > > Regards > -- View this message in context: http://www.nabble.com/Compiler-Error-With-boost%3A%3Abind-and-boost%3A%3Asi… Sent from the Boost - Users mailing list archive at Nabble.com.

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std::wstring issue with Boost::FileSystem
by Sean Farrow 02 Feb '09

02 Feb '09

Hi: Whilst using boost::filesystem I'm getting the following issue: I've defines: std::wstring Process =ProcessToFind; //ProcessToFind is an input to the function I'm writing. std::wstring test =boost::filesystem::wpath(szModName).filename(); //szModName is obtained from a win32 api function. Process.Compare(test); //This line gives the following Error: 1>c:\work\access for everyone\dragonspeak\dragonspeak.cpp(45) : error C2039: 'Compare' : is not a member of 'std::basic_string<_Elem,_Traits,_Ax>' 1> with 1> [ 1> _Elem=wchar_t, 1> _Traits=std::char_traits<wchar_t>, 1> _Ax=std::allocator<wchar_t> 1> ] I'm using the trunk as of yesterday (feb 1) and visual studio 2005. Anyone any ideas what's going wrong, or what I've forgotten? Cheers Sean.

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[Bind] Representing a member function as C function pointer?
by Roland Bock 02 Feb '09

02 Feb '09

Hi, maybe this is stupid, but I wonder if my code could become more elegant. I am using expat for XML parsing, which is working fine, but could be nicer: I have a class (XmlParser) which provides all the handlers for SAX parsing required by expat, but I can't figure out how to use them directly? When initializing expat, I give it a pointer to an XmlParser object and then register handlers: -------------------------- static void expatStartElementHandler (void* pUserData, const char* element, const char** attr) { XmlParser* xmlParser = reinterpret_cast<XmlParser*>(pUserData); xmlParser->startElement (element, attr); } static void expatEndElementHandler (void* pUserData, const char* element) { XmlParser* xmlParser = reinterpret_cast<XmlParser*>(pUserData); xmlParser->endElement (element); } void XmlParser::init() { parser_ = XML_ParserCreate ("UTF-8"); XML_SetUserData (parser_, this); XML_SetElementHandler (parser_, expatStartElementHandler, expatEndElementHandler); //... } ------------------------- I would prefer to get rid of those static non-member functions and their reinterpret_cast and do something like // does not work XML_SetElementHandler (parser_, boost::bind(&XmlParser::startElement, this, _2, _3), boost::bind(&XmlParser::endElement, this, _2)); Is there a nice way to do this with bind? Regards, Roland

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passing a boost.array to a c function, and boost.System
by Sean Farrow 02 Feb '09

02 Feb '09

Hi list: I have a c function EnumProcesses in windows, and waswondering: 1. How can I pass a boost.array to this function, I need to pass the undedrlying array, not the boost.array class. 2. Does boost.system suppor the retrieval of operating system process in an stl-complient way, i.e using stl containers and allowing boost.Foreach to iterate over them. Cheers Sean.

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linking query
by Sean Farrow 01 Feb '09

01 Feb '09

Hi: I've now got boost libraries compiled. The only other query I have is I have my visual studio project set up to use multi-threaded debug dll but when I build with boost filesystem it links the code in by default. How can I tell boost to use the dll version for debug and lib (static) for release? Sean.

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