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+
+// Copyright (C) 2009-2012 Lorenzo Caminiti
+// Distributed under the Boost Software License, Version 1.0
+// (see accompanying file LICENSE_1_0.txt or a copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+// Home at http://www.boost.org/libs/local_function
+
+#include <boost/phoenix/core.hpp>
+#include <boost/phoenix/function.hpp>
+#include <boost/detail/lightweight_test.hpp>
+
+//[phoenix_factorial
+struct factorial_impl { // Phoenix function from global functor.
+ template<typename Sig>
+ struct result;
+
+ template<typename This, typename Arg>
+ struct result<This (Arg)> : result<This (Arg const&)> {};
+
+ template<typename This, typename Arg>
+ struct result<This (Arg&)> { typedef Arg type; };
+
+ template<typename Arg> // Polymorphic.
+ Arg operator()(Arg n) const {
+ return (n <= 0) ? 1 : n * (*this)(n - 1);
+ }
+};
+
+int main(void) {
+ using boost::phoenix::arg_names::arg1;
+
+ boost::phoenix::function<factorial_impl> factorial;
+
+ int i = 4;
+ BOOST_TEST(factorial(i)() == 24); // Call.
+ BOOST_TEST(factorial(arg1)(i) == 24); // Lazy call.
+ return boost::report_errors();
+}
+//]
+