fork download
copy 
  1. #include <iostream>
  2. #include <vector>
  3.  
  4. template<class T, class F1>
  5. class is_functor_enable {
  6. 	struct detector {};
  7. 	template<class Y>
  8. 	static auto search(Y &&)-> std::conditional_t<false, decltype(std::declval<F1>()(std::declval<Y>())), void>;
  9. 	static auto search(...) -> detector;
  10. public:
  11. 	static constexpr bool value = !std::is_same<decltype(search(std::declval<T>())), detector>::value;
  12. };
  13.  
  14. #define GC_IS_HAS_METHOD(_arg_type, _arg_meth_name, ...) ({\
  15. 		auto l = [](auto && lambda_arg) -> std::conditional<false, decltype(std::declval< decltype(lambda_arg) >(). _arg_meth_name ( __VA_ARGS__ )), void> {};\
  16. 		is_functor_enable<_arg_type, decltype(l)>::value;\
  17. 	})
  18.  
  19. int main()
  20. {
  21. 	static_assert(GC_IS_HAS_METHOD(std::vector<int>, foo, 3,4,5,6,7), "ты хуй");
  22. 	std::cout 
  23. 	<< ' ' << GC_IS_HAS_METHOD(std::vector<int>, size, ) //is vector<int> has method size, which takes nothing
  24. 	<< ' ' << GC_IS_HAS_METHOD(std::vector<int>, push_back, std::declval<int &>()) //is vector<int> has method push_back, which takes int &
  25. 	<< ' ' << GC_IS_HAS_METHOD(std::vector<int>, insert, std::declval<std::vector<int>::iterator>(), std::declval<int &>()) //is vector<int> has method insert, which takes iterator and value
  26. 	<< ' ' << GC_IS_HAS_METHOD(std::vector<int>, foo, 3,4,5,6,7) //is vector<int> has method foo, which takes 5 ints
  27. 	;
  28. }
Compilation error #stdin compilation error #stdout 0s 15240KB
comments (?)
stdin
copy 
Standard input is empty
compilation info 
prog.cpp: In function ‘int main()’:
prog.cpp:21:2: error: static assertion failed: ты хуй
  static_assert(GC_IS_HAS_METHOD(std::vector<int>, foo, 3,4,5,6,7), "ты хуй");
  ^~~~~~~~~~~~~
stdout
copy 
Standard output is empty
https://ideone.com/mW8F0g
language:
C++14 (gcc 8.3)
created:
6 years ago
visibility:
secret

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!