Re: [Boost-users] filesystem lambda and for_each

Hi Jean-Christophe,

 40   std::for_each(boost::filesystem::directory_iterator(path), boost::filesystem::directory_iterator(),  41                 str += *boost::lambda::_1.path().parent_path() ); does not compile with the error message that :  error: ‘const struct boost::lambda::lambda_functor >’ has no member named ‘path’

Unfortunately, C++ doesn't allow you to overload the '.' operator, so we have to settle for bind calls. You might try the following: #include #include #include #include <iostream> namespace bf = boost::filesystem; namespace ll = boost::lambda; //tested w/ cygwin g++3, boost 1.44 int main(int argc, char* argv[]) { std::string str = ""; std::string path = "."; std::for_each(bf::directory_iterator(path), bf::directory_iterator(), str += ll::bind(&bf::directory_entry::filename, ll::_1)); std::cout << str << std::endl; return 0; }

I don't understand why and I don't really see how I could have this work. Also, I am wondering why with _1 instead of boost::lambda::_1  I am getting: error: reference to ‘_1’ is ambiguous /usr/local/include/boost/lambda/core.hpp:69:

boost::bind declares _1 in an unnamed namespace, which means that unqualified calls to _1 will usually pick it up (assuming boost::bind has been #included somewhere. I seem to recall that std::bind put its placeholders in std::placeholders instead, I don't know if boost::bind will put them somewhere similar or not. . . HTH, Nate