| |
| // Copyright (C) 2006-2009, 2012 Alexander Nasonov |
| // Copyright (C) 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/scope_exit |
| |
| #include <boost/config.hpp> |
| #if defined(BOOST_NO_CXX11_LAMBDAS) |
| # error "lambda functions required" |
| #elif defined(BOOST_NO_CXX11_VARIADIC_MACROS) |
| # error "variadic macros required" |
| #else |
| |
| #include <boost/scope_exit.hpp> |
| #include <boost/foreach.hpp> |
| #include <boost/typeof/typeof.hpp> |
| #include <boost/typeof/std/vector.hpp> |
| #include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP() |
| #include <boost/detail/lightweight_test.hpp> |
| #include <vector> |
| #include <iostream> |
| #include <sstream> |
| |
| struct person { |
| typedef unsigned int id_t; |
| typedef unsigned int evolution_t; |
| |
| id_t id; |
| evolution_t evolution; |
| |
| person(void) : id(0), evolution(0) {} |
| |
| friend std::ostream& operator<<(std::ostream& o, person const& p) { |
| return o << "person(" << p.id << ", " << p.evolution << ")"; |
| } |
| }; |
| BOOST_TYPEOF_REGISTER_TYPE(person) |
| |
| struct world { |
| world(void) : next_id_(1) {} |
| void add_person(person const& a_person); |
| |
| friend std::ostream& operator<<(std::ostream& o, world const& w) { |
| o << "world(" << w.next_id_ << ", {"; |
| BOOST_FOREACH(person const& p, w.persons_) { |
| o << " " << p << ", "; |
| } |
| return o << "})"; |
| } |
| |
| private: |
| person::id_t next_id_; |
| std::vector<person> persons_; |
| }; |
| BOOST_TYPEOF_REGISTER_TYPE(world) |
| |
| //[world_checkpoint_all |
| void world::add_person(person const& a_person) { |
| persons_.push_back(a_person); |
| |
| // This block must be no-throw. |
| person& p = persons_.back(); |
| person::evolution_t checkpoint = p.evolution; |
| // Capture all by reference `&`, but `checkpoint` and `this` (C++11 only). |
| BOOST_SCOPE_EXIT_ALL(&, checkpoint, this) { // Use `this` (not `this_`). |
| if(checkpoint == p.evolution) this->persons_.pop_back(); |
| }; // Use `;` (not `SCOPE_EXIT_END`). |
| |
| // ... |
| |
| checkpoint = ++p.evolution; |
| |
| // Assign new identifier to the person. |
| person::id_t const prev_id = p.id; |
| p.id = next_id_++; |
| // Capture all by value `=`, but `p` (C++11 only). |
| BOOST_SCOPE_EXIT_ALL(=, &p) { |
| if(checkpoint == p.evolution) { |
| this->next_id_ = p.id; |
| p.id = prev_id; |
| } |
| }; |
| |
| // ... |
| |
| checkpoint = ++p.evolution; |
| } |
| //] |
| |
| int main(void) { |
| person adam, eva; |
| std::ostringstream oss; |
| oss << adam; |
| std::cout << oss.str() << std::endl; |
| BOOST_TEST(oss.str() == "person(0, 0)"); |
| |
| oss.str(""); |
| oss << eva; |
| std::cout << oss.str() << std::endl; |
| BOOST_TEST(oss.str() == "person(0, 0)"); |
| |
| world w; |
| w.add_person(adam); |
| w.add_person(eva); |
| oss.str(""); |
| oss << w; |
| std::cout << oss.str() << std::endl; |
| BOOST_TEST(oss.str() == "world(3, { person(1, 2), person(2, 2), })"); |
| |
| return boost::report_errors(); |
| } |
| |
| #endif // lambda functions and variadic macros |
| |