text: //  ret_test.cpp  - The Boost Lambda Library -----------------------
  //
  // Copyright (C) 2009 Steven Watanabe
  //
  // Distributed under the Boost Software License, Version 1.0. (See
  // accompanying file LICENSE_1_0.txt or copy at
  // http://www.boost.org/LICENSE_1_0.txt)
  //
  // For more information, see www.boost.org
  
  #include <boost/test/minimal.hpp>
  
  #include <boost/lambda/lambda.hpp>
  
  #include <boost/mpl/assert.hpp>
  #include <boost/type_traits/is_same.hpp>
  
  template<class R, class F>
  void test_ret(R r, F f) {
      typename F::result_type x = f();
      BOOST_MPL_ASSERT((boost::is_same<R, typename F::result_type>));
      BOOST_CHECK(x == r);
  }
  
  template<class R, class F, class T1>
  void test_ret(R r, F f, T1& t1) {
      typename F::result_type x = f(t1);
      BOOST_MPL_ASSERT((boost::is_same<R, typename F::result_type>));
      BOOST_CHECK(x == r);
  }
  
  class add_result {
  public:
      add_result(int i = 0) : value(i) {}
      friend bool operator==(const add_result& lhs, const add_result& rhs) {
          return(lhs.value == rhs.value);
      }
  private:
      int value;
  };
  
  class addable {};
  add_result operator+(addable, addable) {
      return add_result(7);
  }
  
  int test_main(int, char*[]) {
      addable test;
      test_ret(add_result(7), boost::lambda::ret<add_result>(boost::lambda::_1 + test), test);
      test_ret(8.0, boost::lambda::ret<double>(boost::lambda::constant(7) + 1));
  
      return 0;
  }
  