boost::function & boost::lambda - call site invocation & accessing _1 and _2 as the type
- by John Dibling
Sorry for the confusing title. Let me explain via code:
#include <string>
#include <boost\function.hpp>
#include <boost\lambda\lambda.hpp>
#include <iostream>
int main()
{
using namespace boost::lambda;
boost::function<std::string(std::string, std::string)> f =
_1.append(_2);
std::string s = f("Hello", "There");
std::cout << s;
return 0;
}
I'm trying to use function to create a function that uses the labda expressions to create a new return value, and invoke that function at the call site, s = f("Hello", "There");
When I compile this, I get:
1>------ Build started: Project: hacks, Configuration: Debug x64 ------
1>Compiling...
1>main.cpp
1>.\main.cpp(11) : error C2039: 'append' : is not a member of 'boost::lambda::lambda_functor<T>'
1> with
1> [
1> T=boost::lambda::placeholder<1>
1> ]
Using MSVC 9.
My fundamental understanding of function and lambdas may be lacking. The tutorials and docs did not help so far this morning.
How do I do what I'm trying to do?
