boost function and boost bind

gistfile1.cpp

#include <Rcpp.h>
using namespace Rcpp;

// [[Rcpp::depends(BH)]]
#include <boost/bind.hpp>
#include <boost/function.hpp>

typedef boost::function<int(int,int)> Combiner;

int add(int x, int y) {
  return x + y;
}

int multiply(int x, int y) {
  return x * y;
}

int add_then_multiply(int x, int y, int factor) {
  return (x + y) * factor;
}

int combine(int x, int y, Combiner combiner) {
  return combiner(x, y);
}

// [[Rcpp::export]]
void applyCombiners(int x, int y) {
  
  Rcout << "add: " << combine(x, y, add) << std::endl;
  
  Rcout << "multiply: " << combine(x, y, multiply) << std::endl;
  
  int factor = 8;
  Rcout << "add_then_multiply: " 
        << combine(x, y, boost::bind(add_then_multiply, _1, _2, factor)) 
        << std::endl;
}


/*** R
applyCombiners(5, 15)
*/