Nat Goodspeed wrote:

Fei Liu wrote:

...

using namespace std; using namespace boost::lambda; using namespace boost; using boost::any_cast;

int main(){ vector<any> a;

std::for_each(a.begin, a.end(), if_then(_1.type() == typeid(int))[cout << _1 << ' ']); }

Invoking a method on a placeholder is a documented limitation:

http://boost.org/doc/html/lambda/le_in_details.html#id1244744

The '.' operator cannot be overloaded. Therefore you must use bind(). Because you're using boost::lambda::if_then, I'm sure you're better off using boost::lambda::bind than plain boost::bind, though the fact that both have been brought into the current namespace makes me think that an explicit reference might help -- something like:

boost::lambda::bind(&any::type, _1)

(Disclaimer: I haven't tried to compile your example, with or without my suggestion.) ______________________________________

Thank you, unfortunately I am getting even more cryptic error messages now after I use explicit bind call: #include <iostream> #include <string> #include <vector> #include <algorithm> #include #include #include #include using namespace std; using namespace boost::lambda; using namespace boost; using boost::any_cast; int main(){ vector<any> a; any val = 3; a.push_back(val); val = string("456"); a.push_back(val); std::for_each(a.begin, a.end(), if_then(boost::lambda::bind(&any::type, _1) == typeid(int))[cout << _1 << ' ']); }