- Boost-users - lists.boost.org

I'm creating an abstraction layer to work with C++, thought you might be interested
by Alan Tennant 10 Mar '10

10 Mar '10

I'm creating an abstraction layer to work with C++, thought you might be interested. Attached are the files required to use it. What it does should be apparent by reading from the top of main () and running the code, you might have to redirect the 4 #includes if you set up your directory structure differently from me. Note stuff.h only contains one function that is required. The program uses an object called obj to achieve the things it does, it does not add this functionality into the bottom level of C++. The key concepts of an obj include: Access members of objects using std::string's Strings can be transferred and stored a lot more easily than types. They can also be combined more easily, a trivial example is ".toString" being made of two parts. Finally they can easily be used as parameters so a function could take some data and member names as parameters. Individual obj members can be added and removed one at a time. One member function can easily be used by several different types. A function can look at aspects of the object it belongs to in order to work out how to behave without any problems or inconsistencies created by the underlying workings of C++. There is no need for all the empty (or otherwise meaningless) member functions that occur near the top of the tree in programs with lots of inheritance, although inheritance possibilities work differently the same sorts of results can be achieved just as easily with less code. CSS like parameters with names and values where any number of them can be used without having to specify the information in advance. Uses boost::any's extensively but you don't have to wrap and unwrap them yourself, less needing to repeat and know definite information about types all the time. Little difference between accessing different types of members such as objects or functions. Want obj's to behave in a fundamentally different way, write members yourself for object without having to edit my files and add them to obj's you create. I'm sure some of this is possible in other ways and put into code as you need it instead of being one big chunk but I think this abstraction layer is useful. I could also use #defines to simplify and enhance the feel of writing code for the user, for example adding some symbols to represent key features instead of having to write a whole word between .'s. It's not as great as it could be at the moment. I think it does everything by copy making it slow and making it so you can't change members when you access them, I wish for it to do everything by pointer to new memory is such a way as it has the Java feal of doing everything the fast way without having to think about it, it could even be smart enough to notice that bools are not efficient this way. I'm not sure how I will fix these things regarding things like how "template <typename T*>" works. Also when you do have to use normal types it might be hard to implement template functions on the obj functions you write. later I will implement removing a member, setting up a type containing various members, more easily creating objects with lots of miscellaneous members (using only one line of code) etc... p.s. I don't have lots of time at the moment to implement due to other commitments, if you like this consider helping with some of it.

1 0

[proto] const-ness of references
by Manjunath Kudlur 10 Mar '10

10 Mar '10

>From reading the documentation, I understand that expressions and objects that are wrapped in proto::terminal<> are held by reference. In the following code, in the "assign" grammar, I match proto::terminal<Var<proto::_> > and call _assign on proto::_value. As expected, a reference to the object held in the terminal gets passed to the callable transform, and I can assign some value to it. template<typename VT> struct Var { VT value; void assign(const VT v) { value = v; } }; struct _assign : proto::callable { typedef void result_type; template<typename VT> result_type operator()(Var<VT> &var) const { var.assign(20); } }; struct assign : proto::or_< proto::when<proto::terminal<Var<proto::_> >, _assign(proto::_value)> > {}; typedef proto::terminal<Var<int> >::type int32_; int main() { int32_ a,b,c; assign()(a); std::cout << proto::value(a).value << std::endl; } Now, I add the following rules to assign grammar : struct assign : proto::or_< proto::when<proto::terminal<Var<proto::_> >, _assign(proto::_value)>, proto::when<proto::assign<proto::terminal<Var<proto::_> >, proto::literal<proto::_> >, _assign(proto::_value(proto::_left), proto::_value(proto::_right))>, proto::when<proto::function<proto::terminal<Var<proto::_> >, proto::literal<proto::_> >, _assign(proto::_value(proto::_left), proto::_value(proto::_right))> > {}; and the following operator() overload to _assign : template<typename VT> result_type operator()(Var<VT> &var, const VT val) const { var.assign(val); } I can merrily call assign()(a=10) and I get the expected behaviour. But when I call assign()(a(20)), I get a compilation error saying that there is no match for operator()(const Var<int> &, const int &). Why is that when I call proto::_value(proto::_left) on a proto::function expression, a *const* reference gets passed to the transform? Did I miss some part of the documentation where this is explained? Manjunath

2 9

template concept question
by Alan Tennant 10 Mar '10

10 Mar '10

I was reading about boosts concepts and I thought. Can I ask inside a template function if a member exists on a parameter of the function. For example. template <typename T> void func(T in) { exists(in, foo); } Where the "exists" line would return true if "in" had a member "foo" otherwise false.

4 9

[Gil new_io] Some questions and remarks
by Olivier Tournaire 10 Mar '10

10 Mar '10

Hi all, I have just checkout gil-contributions svn repo ( http://code.google.com/p/gil-contributions/) in order to test new_io in which I am really interested. Thank you for this very usefull job! I have however some remarks and questions about some compilation issues. 0) The code seems to have been written and tested on Windows. Am I right (see my remarks thereafter)? For ex., why do you use "\\" in paths (paths.hpp) and not "/"? 1) Which Boost version is required? I first tried with 1.40, but it did not work because of missing accessors in boost::gil::variant (index() and bits()). Did they appear in 1.41 or 1.42? With 1.42, this issue is solved. 2) While compiling tests, I ran into some issues. I am running the code on an Ubuntu 9.10, with g++-4.3.4. I was able to fix some of them, but others are still problematic: 2.1) For each test, I have to add at the beginning the 2 following lines: #define BOOST_TEST_DYN_LINK #define BOOST_TEST_MODULE my application tests It probably comes from my little knowledge of boost unit_test_framework. Could you explain? 2.2) For each test, the compiler gave the following error: /usr/local/include/boost/gil/extension/io_new/detail/dynamic_io_new.hpp:75: error: there are no arguments to ‘io_error’ that depend on a template parameter, so a declaration of ‘io_error’ must be available I simply add in *[...]/detail/dynamic_io_new.hpp* an unclude directive at the beginning of the file : #include <boost/gil/extension/io/io_error.hpp>. Still do not understand how it can work wihtout this ... 2.3) I had a similar error with *[...]/formats/bmp/read.hpp*: /usr/local/include/boost/gil/extension/io_new/formats/bmp/read.hpp:833: error: there are no arguments to ‘get_info’ that depend on a template parameter, so a declaration of ‘get_info’ must be available I simply changed line 833 from get_info() to parent_t::get_info(). Now works. 2.4) Some typename are missing (still do not know how visual can infer types ...): - [...]/formats/jpeg/read.hpp, line 336: *typename*Image::view_t - [...]/formats/bmp/is_allowed.hpp, line 73: *typename*View::value_type - [...]/formats/pnm/read.hpp, line 419: *typename* Image::view_t Everything works with these changes. 2.5) png_read_test failed. Obviously, this is a portability issue. PNG filenames for testing are uppercase, while they are lowercase in the test code. I think that is also missing in the code the path to png files. For example, in basic_format_test, instead of test_file< gray1_image_t >( "basn0g01.png" ); it soulhd be: test_file< gray1_image_t >(* png_in + "BASN0G01.PNG"* ); I did not rename all files, so I am unable to try the test. 2.6) Some tests fail to compile or link. Here are the errors: - *all_formats_test.cpp*: In file included from /usr/include/png.h:481, from /usr/local/include/boost/gil/extension/io_new/png_tags.hpp:23, from /usr/local/include/boost/gil/extension/io_new/png_read.hpp:22, from /usr/local/include/boost/gil/extension/io_new/png_all.hpp:22, from /home/olivier/work/dev/lib/gil-contributions-read-only/gil_2/libs/gil/io_new/test/all_formats_test.cpp:7: /usr/include/pngconf.h:335: error: expected constructor, destructor, or type conversion before ‘.’ token /usr/include/pngconf.h:336: error: ‘__dont__’ does not name a type - *pnm_reads_test.cpp*: pnm_read_test.cpp.o: In function `pnm_test::read_header_test::test_method()': pnm_read_test.cpp:(.text+0x24c0): undefined reference to `boost::gil::pnm_image_type::_color_asc' collect2: ld returned 1 exit status Do not really understand since _color_asc is a typedef defined in pnm_tags.hpp ... - *jpeg_old_test.cpp* (sorry for the message ...): /usr/local/include/boost/gil/extension/io_new/formats/jpeg/write.hpp: In function ‘typename BinaryOp::result_type boost::gil::detail::apply_operation(const boost::gil::variant<Types>&, const Info&, BinaryOp) [with Types1 = boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgba8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgb8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray16_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray8_pixel_t*> > >, boost::mpl::vector0<mpl_::na>, 0>, 0>, 0>, 0>, Info = boost::gil::image_write_info<boost::gil::jpeg_tag, boost::gil::detail::no_log>, BinaryOp = boost::gil::detail::dynamic_io_fnobj<boost::gil::detail::jpeg_write_is_supported, boost::gil::detail::writer<boost::gil::detail::file_stream_device<boost::gil::jpeg_tag>, boost::gil::jpeg_tag, boost::gil::detail::no_log> >]’: /usr/local/include/boost/gil/extension/io_new/formats/jpeg/write.hpp:283: instantiated from ‘void boost::gil::detail::dynamic_image_writer<Device, boost::gil::jpeg_tag, boost::gil::detail::no_log>::apply(const boost::gil::any_image_view<Views>&, const boost::gil::image_write_info<boost::gil::jpeg_tag, boost::gil::detail::no_log>&) [with Views = boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgba8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgb8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray16_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray8_pixel_t*> > >, boost::mpl::vector0<mpl_::na>, 0>, 0>, 0>, 0>, Device = boost::gil::detail::file_stream_device<boost::gil::jpeg_tag>]’ /usr/local/include/boost/gil/extension/io_new/detail/write_view.hpp:302: instantiated from ‘void boost::gil::write_view(Device&, const boost::gil::any_image_view<Types2>&, const boost::gil::image_write_info<FormatTag, Log>&, typename boost::enable_if<typename boost::mpl::and_<typename boost::gil::detail::is_output_device<IODevice>::type, typename boost::gil::is_format_tag<FormatTag>::type, mpl_::bool_<true>, mpl_::bool_<true>, mpl_::bool_<true> >::type, void>::type*) [with Device = boost::gil::detail::file_stream_device<boost::gil::jpeg_tag>, Views = boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgba8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgb8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray16_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray8_pixel_t*> > >, boost::mpl::vector0<mpl_::na>, 0>, 0>, 0>, 0>, FormatTag = boost::gil::jpeg_tag, Log = boost::gil::detail::no_log]’ /usr/local/include/boost/gil/extension/io_new/detail/write_view.hpp:357: instantiated from ‘void boost::gil::write_view(const String&, const boost::gil::any_image_view<Types2>&, const boost::gil::image_write_info<FormatTag, Log>&, typename boost::enable_if<typename boost::mpl::and_<typename boost::gil::detail::is_supported_path_spec<P>::type, typename boost::gil::is_format_tag<FormatTag>::type, mpl_::bool_<true>, mpl_::bool_<true>, mpl_::bool_<true> >::type, void>::type*) [with String = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, Views = boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgba8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgb8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray16_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray8_pixel_t*> > >, boost::mpl::vector0<mpl_::na>, 0>, 0>, 0>, 0>, FormatTag = boost::gil::jpeg_tag, Log = boost::gil::detail::no_log]’ /usr/local/include/boost/gil/extension/io_new/jpeg_io_old.hpp:169: instantiated from ‘void boost::gil::jpeg_write_view(const String&, const View&, int) [with String = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, View = boost::gil::any_image_view<boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgba8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgb8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray16_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray8_pixel_t*> > >, boost::mpl::vector0<mpl_::na>, 0>, 0>, 0>, 0> >]’ /home/olivier/work/dev/lib/gil-contributions-read-only/gil_2/libs/gil/io_new/test/jpeg_old_test.cpp:98: instantiated from here /usr/local/include/boost/gil/extension/io_new/formats/jpeg/write.hpp:243: error: invalid initialization of non-const reference of type ‘boost::gil::variant<boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgba8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgb8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray16_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray8_pixel_t*> > >, boost::mpl::vector0<mpl_::na>, 0>, 0>, 0>, 0> >::base_t&’ from a temporary of type ‘boost::gil::variant<boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgba8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgb8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray16_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray8_pixel_t*> > >, boost::mpl::vector0<mpl_::na>, 0>, 0>, 0>, 0> >::base_t’ /usr/local/include/boost/gil/extension/io_new/formats/jpeg/write.hpp:213: error: in passing argument 1 of ‘typename Op::result_type boost::gil::detail::apply_operation_base(Bits&, size_t, const Info&, Op) [with Types = boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgba8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgb8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray16_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray8_pixel_t*> > >, boost::mpl::vector0<mpl_::na>, 0>, 0>, 0>, 0>, Info = boost::gil::image_write_info<boost::gil::jpeg_tag, boost::gil::detail::no_log>, Bits = boost::gil::variant<boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgba8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::rgb8_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray16_pixel_t*> > >, boost::mpl::v_item<boost::gil::image_view<boost::gil::memory_based_2d_locator<boost::gil::memory_based_step_iterator<boost::gil::gray8_pixel_t*> > >, boost::mpl::vector0<mpl_::na>, 0>, 0>, 0>, 0> >::base_t, Op = boost::gil::detail::dynamic_io_fnobj<boost::gil::detail::jpeg_write_is_supported, boost::gil::detail::writer<boost::gil::detail::file_stream_device<boost::gil::jpeg_tag>, boost::gil::jpeg_tag, boost::gil::detail::no_log> >]’ /usr/local/include/boost/gil/extension/io_new/formats/jpeg/write.hpp:243: error: return-statement with a value, in function returning 'void' Apart png_read_test and its case sensitive problem, all compiled and linked tests run successfully. This is a really good new! However, could you please help regarding the issues above? Please note that if you are intersted in a Linux developper/tester for gil, I am wiling to do some jobs ... Best regards, Olivier

3 8

Re: [Boost-users] [Regex] Accessing match count
by ninti＠internode.on.net 10 Mar '10

10 Mar '10

The regexes in my previous post may be borked due to email client stripping stuff out. Let's just assume that regex_consonant and regex_vowel are well formed patterns. The code below seems to be getting closer. It returns a plausible count for number of matches of regex 'expression' in string 'word': string get_m(string word) { regex c("^" + regex_consonant); regex v(regex_vowel + "$"); string re = "(" + regex_vowel + "+" + regex_consonant + "+)"; regex expression(re); string replacement = ""; word = regex_replace(word, c, replacement); word = regex_replace(word, v, replacement); boost::sregex_token_iterator itr(word.begin(), word.end(), expression); boost::sregex_token_iterator end; int size = 0; for(; itr != end; ++itr) { size++; } string s; stringstream out; out << size; s = out.str(); return s; } Is boost::sregex_token_iterator the appropriate function for subsequently counting the number of matches found in a given string? Also, don't hold back on how bad this code is, I'm here to learn! Mick

2 1

boost::timer elapsed time
by zbierak 10 Mar '10

10 Mar '10

Hi, I've been having a problem recently with boost::timer. I have the following code: #include <iostream> #include <boost/timer.hpp> int main() { boost::timer t; // (here: some initialization stuff) t.restart(); // (here: a job that takes several seconts) std::cout << "Total time: " << t.elapsed() << "s." << std::endl; } While on my windows machine it displays the correct time, when I compile it on Ubuntu, it constantly displays zero seconds, regardless how long the job really takes. Do you have any ideas why that might be happening? I'm using boost 1.40 and Ubuntu 9.04. Thanx in advance! -- View this message in context: http://old.nabble.com/boost%3A%3Atimer-elapsed-time-tp27846807p27846807.html Sent from the Boost - Users mailing list archive at Nabble.com.

2 1

[Fusion] The very basics!
by Robert Jones 10 Mar '10

10 Mar '10

I don't mind admitting that I'm finding Fusion a struggle to get my head round; there's something about the compile time/run time duality that makes my brain hurt! So, a really basic question... When I write this, pretty much verbatim from the examples, despite there being the appearance of a loop, this is in fact a linear invocation of three calls to print::operator(), and since the fusion vector is entirely known at compile time, as all fusion types must be, regardless of how constructed, this "loop" is completely "unrolled" at compile time. Is this correct? Thanks, - Rob. #include <typeinfo> #include <iostream> #include <boost/fusion/include/sequence.hpp> #include <boost/fusion/include/algorithm.hpp> struct print { template <typename T> void operator()(T const& x) const { std::cout << x << " "; } }; int main( ) { using namespace boost::fusion; vector<int, char, std::string> stuff(1, 'x', "howdy"); for_each(stuff, print()); std::cout << std::endl; }

2 1

Can't compile boost::asio
by Daniel V 10 Mar '10

10 Mar '10

Hi, I'm trying to compile the client example found in http://www.boost.org/doc/libs/1_42_0/doc/html/boost_asio/tutorial/tutdaytim… tutorials), but I get the following errors: g++ -o dist/Debug/GNU-MacOSX/socketclient build/Debug/GNU-MacOSX/main.o Undefined symbols: "boost::system::get_system_category()", referenced from: boost::asio::error::get_system_category() in main.o boost::system::error_code::error_code()in main.o __static_initialization_and_destruction_0(int, int)in main.o __static_initialization_and_destruction_0(int, int)in main.o "boost::system::get_generic_category()", referenced from: __static_initialization_and_destruction_0(int, int)in main.o __static_initialization_and_destruction_0(int, int)in main.o __static_initialization_and_destruction_0(int, int)in main.o ld: symbol(s) not found collect2: ld returned 1 exit status make[2]: *** [dist/Debug/GNU-MacOSX/socketclient] Error 1 make[1]: *** [.build-conf] Error 2 make: *** [.build-impl] Error 2 BUILD FAILED (exit value 2, total time: 2s) Any idea why this is failing? Thanks Dann

7 7

[Regex] Accessing match count
by ninti＠internode.on.net 10 Mar '10

10 Mar '10

Newbie here trying to reimplement PHP's preg_match_all() function in C++. I'm rewriting a PHP class which functions as a Porter Stemmer. I seem to have the regex_replace code working nicely but am now stuck on regex_match/regex_search. I want to count the number of times a regex matches within a string. The regex attempts to match all occurrences of one+ vowels followed by one+ consonants (known as 'm' or measure, roughly equivalent to a syllable). The original PHP function is as follows: private static function m($str) { $c = '(?:[bcdfghjklmnpqrstvwxz]|(?<=[aeiou])y|^y)'; $v = '(?:[aeiou]|(?<![aeiou])y)'; $str = preg_replace("#^$c+#", '', $str); $str = preg_replace("#$v+$#", '', $str); preg_match_all("#($v+$c+)#", $str, $matches); return count($matches[1]); } So all I'm interested in here is the number of matches. I'm afraid I'm not even really sure which boost regex function I should be using, it seems like regex_search may be the correct choice as I'm not matching a whole string. This is what I've got so far: using namespace std; using namespace boost; string regex_vowel = "(?:[aeiou]|(?<![aeiou])y)"; string regex_consonant = "(?:[bcdfghjklmnpqrstvwxz]|(?<=[aeiou])y|^y)"; string get_m(string word) { regex c("^" + regex_consonant); regex v(regex_vowel + "$"); string replacement = ""; word = regex_replace(word, c, replacement); word = regex_replace(word, v, replacement); [ ... so far so good, this does the same as the first four lines of the PHP code above ... ] string re = "(" + regex_vowel + "+" + regex_consonant + "+)"; regex expression(re); string::const_iterator start, end; start = word.begin(); end = word.end(); match_results<string::const_iterator> what; match_flag_type flags = match_default | match_partial; regex_search(start, end, what, expression, flags); string thing = what[1]; int size = thing.size(); cout << what[1] << endl; string s; stringstream out; out << size; s = out.str(); return s; } This does not replicate the last two lines of PHP code above, instead returning the number of characters in a substring of sorts. So yes, I'm lost! Have tried several variations/possibilities but can't find a good example to work with. Have tried some much simpler variations they're not working either. TIA for any tips, even on which regex function I should be using. Mick

1 0

[filesystem] basic_path as parameter
by Alex Lamaison 10 Mar '10

10 Mar '10

I'd like to use basic_path as a function parameter so that it works correctly whether a wide or narrow string is passed. template<typename T> void func(basic_path<T> file) { do thing to file } func("myfile"); func(L"myfile"); However I can't do this because basic_path has a second Traits template parameter which is not itself a template. So I tried the following workaround: template<typename T> struct traits_chooser; template<> struct traits_chooser<char*> { typedef boost::filesystem::path_traits traits; }; template<> struct traits_chooser<wchar_t*> { typedef boost::filesystem::wpath_traits traits; }; template<typename T> void func(basic_path<T, typename traits_chooser<T>::traits> file) {...} But my compiler (MSVC 2005) still can't deduce the parameter type. Does anyone know how I can get this to work? Many thanks. Alex Lamaison

3 4