1 2 // Copyright (C) 2009-2012 Lorenzo Caminiti 3 // Distributed under the Boost Software License, Version 1.0 4 // (see accompanying file LICENSE_1_0.txt or a copy at 5 // http://www.boost.org/LICENSE_1_0.txt) 6 // Home at http://www.boost.org/libs/local_function 7 8 #include <boost/phoenix/core.hpp> 9 #include <boost/phoenix/function.hpp> 10 #include <boost/detail/lightweight_test.hpp> 11 12 //[phoenix_factorial 13 struct factorial_impl { // Phoenix function from global functor. 14 template<typename Sig> 15 struct result; 16 17 template<typename This, typename Arg> 18 struct result<This (Arg)> : result<This (Arg const&)> {}; 19 20 template<typename This, typename Arg> 21 struct result<This (Arg&)> { typedef Arg type; }; 22 23 template<typename Arg> // Polymorphic. operator ()factorial_impl24 Arg operator()(Arg n) const { 25 return (n <= 0) ? 1 : n * (*this)(n - 1); 26 } 27 }; 28 main(void)29int main(void) { 30 using boost::phoenix::arg_names::arg1; 31 32 boost::phoenix::function<factorial_impl> factorial; 33 34 int i = 4; 35 BOOST_TEST(factorial(i)() == 24); // Call. 36 BOOST_TEST(factorial(arg1)(i) == 24); // Lazy call. 37 return boost::report_errors(); 38 } 39 //] 40 41