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  1. #include <string>
  2. #include <iostream>
  3. #include <boost/bind.hpp>
  4. #include <boost/typeof/typeof.hpp>
  5.  
  6. struct overloaded
  7. {
  8.     typedef int result_type;
  9.  
  10.     int operator()(const std::string& s) const { return 1; }
  11.     int operator()(double d)             const { return 2; }
  12. };
  13.  
  14. struct factory
  15. {
  16.     template <typename T> struct result { typedef BOOST_TYPEOF_TPL(boost::bind(overloaded(), T())) type; };
  17.  
  18.     template <typename T>
  19.     typename result<T>::type operator()(T t) const 
  20.     {
  21.         return boost::bind(overloaded(), t);
  22.     }
  23. };
  24.  
  25. int main()
  26. {
  27.     overloaded foo;
  28.  
  29.     // based on local bind expression:
  30.     BOOST_AUTO(unresolved, boost::bind(foo, _1));
  31.     std::cout << unresolved("3.14") << std::endl;  // should print 1
  32.     std::cout << unresolved(3.14)   << std::endl;  // should print 2
  33.  
  34.     // based on a factory function template
  35.     factory makefoo;
  36.     std::cout << makefoo("3.14")() << std::endl;  // should print 1
  37.     std::cout << makefoo(3.14)()   << std::endl;  // should print 2
  38. }
Success #stdin #stdout 0s 2856KB
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https://ideone.com/VHcEC
language:
C++ (gcc 8.3)
created:
13 years ago
visibility:
secret

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