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Diffstat (limited to 'boost/make_default.hpp')
| -rw-r--r-- | boost/make_default.hpp | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/boost/make_default.hpp b/boost/make_default.hpp new file mode 100644 index 0000000000..b8255feead --- /dev/null +++ b/boost/make_default.hpp @@ -0,0 +1,40 @@ +/// @file +// Copyright (c) 2009-2014 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 |