On a Metrowerks version which has not been announced (much less released):
#include <string> #include <vector> #include <algorithm> #include <bind> using namespace std::tr1; using namespace std::tr1::placeholders; struct test { int i; std::string s; }; std::vector<test> tests;
void set(int & i, int val) { i = val; } int main(int argc, char* argv[]) { std::for_each( tests.begin(), tests.end(), bind(&set, bind(mem_fn(&test::i),_1), 10) ); return 0; }
Sorry, I mis-explained. For boost::bind, the above works like a bliss. It will have problems working with other code, that uses result_type. For example, boost::transform_iterator: #include <boost/bind.hpp> #include <boost/iterator/transform_iterator.hpp> using namespace boost; #include <algorithm> #include <vector> #include <string> struct test { std::string s; }; void clear_s( std::string & s) { s.erase(); } int main(int argc, char* argv[]) { std::vector<test> v; std::for_each( // of course, it would be simpler to use Range Template Library :D make_transform_iterator(v.begin(),mem_fn(&test::s)), make_transform_iterator(v.end(),mem_fn(&test::s)), clear_s); return 0; } c:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\algorithm(21) : error C2664: 'void (std::string &)' : cannot convert parameter 1 from 'const std::string' to 'std::string &' Conversion loses qualifiers d:\john\buff\testbind2\testbind2\testbind2.cpp(23) : see reference to function template instantiation '_Fn1 std::for_each<boost::transform_iterator<UnaryFunction,Iterator,Reference,Value>,void(__cdecl *)(std::string &)>(_InIt,_InIt,_Fn1)' being compiled with [ _Fn1=void (__cdecl *)(std::string &), UnaryFunction=boost::_mfi::dm<std::string,test>, Iterator=std::vector<test>::iterator, Reference=boost::use_default, Value=boost::use_default, _InIt=boost::transform_iterator<boost::_mfi::dm<std::string,test>,std::vector<test>::iterator,boost::use_default,boost::use_default> ] That's why I said we should have two classes - one that defines: typedef R const & result_type; and one that defines: typedef R & result_type; So you can clearly choose if you treat your sequence as const or not. Best, John