February 2014 - Boost-users - lists.preview.boost.org

BOOST Spirit Qi and lexer parsing of tokens
by Howard, Tony 07 Feb '14

07 Feb '14

Hi, I am starting a project that will use spriti Qi and a lexer. I am having difficulty getting something simple to parse correctly without having to add states and just want to make sure I am going about it the right way. I have a label that should parse the following example (where the label starts/ends with a single quote): 'this is my BOOLEAN 123label 12as' And then this label will be followed by zero or more blanks and then a number enclosed in parenthesis: ( 123 ) There are a number of arbitrary blanks in between the number and the enclosing parenthesis. I am ignoring blanks and whitespace in the default state of the lexer (assume blanks and white spaces are defined in the patterns referenced): this->self += lex::token_def<>("{BLANK}")[ lex::_pass = lex::pass_flags::pass_ignore ]; this->self += lex::token_def<>("{WS}")[ lex::_pass = lex::pass_flags::pass_ignore ]; The first problem I encountered was that if I ignored blanks in the initial state and tried to parse a label that contains blanks that I don't want to ignore, this was not possible. So I had to create a label state, to which the blank token is added, and am switching to this state initially using in_state[...] so that when we are done with the label, we return to the initial state, where blanks are once again ignored. This worked. The problem then came with the digits. Since the digits were already recognized in the label state, I could not also recognize them in the initial state. So I added a digit state, where the digit token is now defined and the label state has to transition to this state while parsing between letter, symbols and digits (and whatever else I decide is allowed to make up my label), and after I get out of the label state, my rule parses a parenthesis, goes into the digit state, and then parses the closing parenthesis. This works correctly for what I need now. The issue I am having is looking ahead. What if a rule needs lower case letters only? I will have to create a state for it, remove it from the label state, etc. I will have to do this for any core patterns, which to me seems like there should be an easier way to do this. Any suggestions, comments, concerns? I have code snippets if my approach is not clear. Thanks for your help. Tony.

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FileSystem: crash on OSX 10.8 with create_directory
by Tim Burgess 07 Feb '14

07 Feb '14

Hi, My app crashes out when I run the following: boost::filesystem::path myPath = wxStandardPaths::Get().GetConfigDir().ToStdWstring(); if (myPath.has_filename()) { myPath.remove_filename(); } // Add the company name and check for directory existence myPath /=wstrRBCompanyName; if (!boost::filesystem::exists(myPath)) { // The following test displays the path I'd expect to see (/library/Raised Bar in my case) wxMessageBox( myPath.native(), wstrErrorTitle, wxOK | wxICON_EXCLAMATION); // Create the required directory - displays a message box indicating deletion of a lock file here and the app exits boost::filesystem::create_directory(myPath); } This code appears to work fine on Windows, but fails on OSX 10.8. I should point out that I'm a blind programmer and I'm struggling to get Apple's VoiceOver utility to interact in a useful manner with Xcode 5's debugger and that's why I'm using a wxMessageBox to try and track down my failure. Best wishes. Tim

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Build: Clang, libstdc++ and Mac 10.8
by Tim Burgess 07 Feb '14

07 Feb '14

Hi, Due to the requirements of another library I have to use, I need to build Boost 1.55.0 on my Mac 10.8 system using the libstdc++ STL library, rather then libc++. I've now got myself royally confused with the build configuration process, as to where I specify toolsets and other options to achieve what I need. I'm failing with: Cd /users/tim/developer/libraries/boost_1_55_0 ./b2 clean sudo sh bootstrap.sh macosx-version=10.8 macosx-version-min=10.7 architecture=combined threading=multi link=static address-model=32_64 ./b2 toolset=clang -std=c++11 cxxflags="-stdlib=libstdc++" linkflags="-stdlib=libstdc++" I don't actually need the c++11 support. Can anybody advise, please? Best wishes. Tim Burgess

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lexical_cast: fatal error
by Tim Burgess 07 Feb '14

07 Feb '14

Hi, Using 1.55.0 in my Xcode project with clang as the compiler I'm getting: "/boost/type_traits/is_fundamental.hpp:26:20: fatal error: recursive template instantiation exceeded maximum depth of 128"::boost::is_arithmetic<T>::value This error is triggered by me including lexical_cast.hpp. Has anybody else encountered this and, if so, found a solution, please? Best wishes. Tim Burgess

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Boost Accumulators Tail
by Jon Lederman 06 Feb '14

06 Feb '14

Hi, I am a newbie to using boost accumulators. I have tried a simple program using examples from the boost website. I have something as simple as: #include <boost/accumulators/accumulators.hpp> #include <boost/accumulators/statistics/stats.hpp> #include <boost/accumulators/statistics/tail.hpp> include <boost/accumulators/statistics/tail_quantile.hpp> using namespace boost::accumulators; typedef accumulator_set<double, stats<tag::tail_quantile<right> > > accumulator_t_right; typedef accumulator_set<double, stats<tag::tail_quantile<left> > > accumulator_t_left; accumulator_t_right acc0( tag::tail<right>::cache_size = 1000 ); accumulator_t_right acc1( tag::tail<right>::cache_size = 1000 ); accumulator_t_left acc2( tag::tail<left>::cache_size = 1000 ); accumulator_t_left acc3( tag::tail<left>::cache_size = 1000 ); I am met with: /usr/local/src/freeswitch/src/mod/applications/mod_soundtouch/mod_soundtouch.cpp:56:63: error: template argument 1 is invalid /usr/local/src/freeswitch/src/mod/applications/mod_soundtouch/mod_soundtouch.cpp:56:65: error: template argument 1 is invalid /usr/local/src/freeswitch/src/mod/applications/mod_soundtouch/mod_soundtouch.cpp:56:67: error: template argument 2 is invalid /usr/local/src/freeswitch/src/mod/applications/mod_soundtouch/mod_soundtouch.cpp:56:88: error: invalid type in declaration before ';' token /usr/local/src/freeswitch/src/mod/applications/mod_soundtouch/mod_soundtouch.cpp:57:62: error: template argument 1 is invalid /usr/local/src/freeswitch/src/mod/applications/mod_soundtouch/mod_soundtouch.cpp:57:64: error: template argument 1 is invalid /usr/local/src/freeswitch/src/mod/applications/mod_soundtouch/mod_soundtouch.cpp:57:66: error: template argument 2 is invalid /usr/local/src/freeswitch/src/mod/applications/mod_soundtouch/mod_soundtouch.cpp:57:86: error: invalid type in declaration before ';' token /usr/local/src/freeswitch/src/mod/applications/mod_soundtouch/mod_soundtouch.cpp:59:42: error: template argument 1 is invalid /usr/local/src/freeswitch/src/mod/applications/mod_soundtouch/mod_soundtouch.cpp:59:56: error: expected unqualified-id before '=' token /usr/local/src/freeswitch/src/mod/applications/mod_soundtouch/mod_soundtouch.cpp:60:42: error: template argument 1 is invalid /usr/local/src/freeswitch/src/mod/applications/mod_soundtouch/mod_soundtouch.cpp:60:56: error: expected unqualified-id before '=' token /usr/local/src/freeswitch/src/mod/applications/mod_soundtouch/mod_soundtouch.cpp:61:41: error: template argument 1 is invalid /usr/local/src/freeswitch/src/mod/applications/mod_soundtouch/mod_soundtouch.cpp:61:55: error: expected unqualified-id before '=' token /usr/local/src/freeswitch/src/mod/applications/mod_soundtouch/mod_soundtouch.cpp:62:41: error: template argument 1 is invalid /usr/local/src/freeswitch/src/mod/applications/mod_soundtouch/mod_soundtouch.cpp:62:55: error: expected unqualified-id before '=' token Do I need to use a specific namespace for the right and left arguments? Where are these defined? Or is something else wrong. Any help would be greatly appreciated. Thank you in advance. Regards, Jon

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Building Boost dynamically linkable gives linking error?
by Mehmet Emin Erük 06 Feb '14

06 Feb '14

I am trying to build boost and generate dll's but whatever I have done did not solve the problem. Here what I have got: Creating library bin.v2\libs\thread\build\msvc-11.0\dbg\adrs-mdl-32\async-excpt-on\thrd-mlt\boost_thread-vc110-mt-gd-1_53.lib and object bin.v2\libs\thread\build\msvc-11.0\dbg\adrs-mdl-32\async-excpt-on\thrd-mlt\boost_thread-vc110-mt-gd-1_53.exp thread.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __thiscall boost::gregorian::greg_month::greg_month(unsigned short)" (__imp_??0greg_month@gregorian@boost@@QAE@G@Z) referenced in function "public: __thiscall boost::gregorian::date::date(enum boost::date_time::special_values)" (??0date@gregorian@boost@@QAE@W4special_values@date_time@2@@Z) thread.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __thiscall boost::gregorian::greg_month::operator unsigned short(void)const " (__imp_??Bgreg_month@gregorian@boost@@QBEGXZ) referenced in function __catch$?make_external_thread_data@?A0x9b8c45f0@boost@@YAXXZ$0 bin.v2\libs\thread\build\msvc-11.0\dbg\adrs-mdl-32\async-excpt-on\thrd-mlt\boost_thread-vc110-mt-gd-1_53.dll : fatal error LNK1120: 2 unresolved externals Here some information about the setup: OS: W7 x64 Command to build: b2 -j%NUMBER_OF_PROCESSORS% --abbreviate-paths toolset=msvc-11.0 define=_SECURE_SCL=0 define=_CRT_SECURE_NO_DEPRECATE define=_CRT_SECURE_NO_WARNINGS --without-mpi address-model=32 variant=debug install link=shared runtime-link=shared threading=multi asynch-exceptions=on exception-handling=on extern-c-nothrow=off --prefix=..\boost cd .. I have CYGWin installed to the computer. *Here what I have tried till now;* *I have tried to build it in 32 bit command window (I am using jenkins to build boost) <tns:build tns:position='boost/boost_1_53_0' tns:command='C:\Windows\SysWOW64\cmd /C bootstrap.bat'/> <tns:build tns:position='boost/boost_1_53_0' tns:command='C:\Windows\SysWOW64\cmd /C build_boost-win32-debug-vs2012.cmd'/> *I wrote #define BOOST_ALL_DYN_LINK in the boost config/user.hpp *I wrote #define BOOST_ALL_NO_LIB in the boost config/user.hpp Is there anyone who experienced such a problem before? I really could not find anything in anywhere? -- bir gün herkes özgür olacak

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[Move, Container] returning a move-only type
by John M. Dlugosz 05 Feb '14

05 Feb '14

The definition of boost::container::vector includes: BOOST_COPYABLE_AND_MOVABLE rather than BOOST_MOVABLE_BUT_NOT_COPYABLE if the element type cannot be copied. If I have: typedef boost::container::vector<MyType> VecType; VecType foo() { ⋮ return boost::move(some_other_vec); } VecType x= foo(); On a configuration with BOOST_NO_RVALUE_REFERENCES defined, this gives an error within VecType's copy constructor, since MyType cannot be copied. If I write VecType x= boost::move(foo()); then I get an error that no matching move is viable, as the move(T&) wants an lvalue as the argument. I can't write the return type of foo to be rv<VecType> because that can't be copied (fake move-out like auto_pointer) either; the members are declared private and never defined. I'm thinking that if VecType were BOOST_MOVABLE_BUT_NOT_COPYABLE then it would work as expected, since operator rv<VecType>& would be provided. How can I make this work without surgery on the Boost headers, and hopefully without something ugly like deriving from vector and having to re-define and forward all the various constructors and such? —John

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[Range, Container] range of to-be-moved values ?
by John M. Dlugosz 05 Feb '14

05 Feb '14

Given a boost::container::vector<C> vec; I can write vec.push_back(move(value)) for a move-only (non-copyable) type C, instead of vec.push_back(value) as usual. But what would I write instead of vec.insert(pos,b,e) where (b,e] is a range of values? I'm particularly fond of Range concept, rather than loose iterators, so my function would be something that takes something that works as a Range; e.g. template <typename R> void prepend (const R& src_range) { auto b= boost::begin(src_range); auto e= boost::end(src_range); vec.insert(vec.begin(), b, e); } An rvalue reference to a range is not the same thing as a range of values that I may move from. I could have a differently named function and pass it a range with the implicit assumption that the function will modify the values, but is there a proper way to indicate that as part of the type? src_range can be, say, a pair of (non-const) iterator s as opposed to a pair of const_iterator s, or otherwise range_iterator<R>::type is dereferencable to a const value or not. But that itself is hard to see in general let alone overload against! If my function were called prepend_and_destroy_original(src) it might clue in the caller, but in general it is surprising that a parameter of (const R&) will modify the values. src itself doesn't change, and now refers to the same range of values which are now swapped out with defaults. With built-in pointers and even shared_ptr I can distinguish between an in-out parameter and a parameter that dereferences to a modifiable or const value. But what about with Ranges? Even with lower-case ranges provided by two iterators, How can you call something like boost::container::vector v2 (InIt_start, InIt_end); to convert a std::vector or some other container of move-only items? Only if the types match exactly can the vector(vector&&) constructor be used. —John

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[iostreams] Why does boost::iostreams::copy close the Sink & Source?
by Sebastian Karlsson 05 Feb '14

05 Feb '14

What's the rationale behind this decision? I don't find it intuitive and reduces the utility of the function. In my case I read from a file into a stream which I want to later use, the signature of the device is important. But as soon as I've copied my data over to the device it's destroyed and along side the data goes down the drain. Kind regards, Sebastian Karlsson

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Boost.MultiIndex. Using several keys together.
by syvyi 05 Feb '14

05 Feb '14

Hello, there's a structure struct person { std::string name; std::string surname; int birth_year; std::string craft; }; How to create such a multiindex container that dumping could performed using an index as name, surname and year triple alltogether? -- View this message in context: http://boost.2283326.n4.nabble.com/Boost-MultiIndex-Using-several-keys-toge… Sent from the Boost - Users mailing list archive at Nabble.com.

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