/// @file // Copyright (c) 2009-2016 Vladimir Batov. // Use, modification and distribution are subject to the Boost Software License, // Version 1.0. See http://www.boost.org/LICENSE_1_0.txt. #ifndef BOOST_MAKE_DEFAULT_HPP #define BOOST_MAKE_DEFAULT_HPP namespace boost { /// @details A considerable number of libraries require an instance of a class /// provided (storage created and initialized). For example, /// @code /// Type result; /// ... /// istream >> result; /// @endcode /// In generic code that results in the Default Constructibility requirement imposed /// on every type 'Type' to be used with the respective code. Inevitably, that requirement /// a) either excludes all the classes that for various reasons do not meet that requirement or /// b) imposes certain (not necessarily desirable) design/implementation onto respective classes. /// /// Deployment of boost::make_default() eliminates the Default Constructibility requirement with /// @code /// Type result = boost::make_default<Type>(); /// ... /// istream >> result; /// @endcode /// Classes with no default constructor can now be included via a boost::make_default() specialization: /// @code /// namespace boost /// { /// template<> inline Type make_default<Type>() { return Type(parameters); } /// } /// @endcode template<typename T> T make_default() { return T(); } } #endif // BOOST_MAKE_DEFAULT_HPP