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1 | /// @file | |
2 | // Copyright (c) 2009-2016 Vladimir Batov. | |
3 | // Use, modification and distribution are subject to the Boost Software License, | |
4 | // Version 1.0. See http://www.boost.org/LICENSE_1_0.txt. | |
5 | ||
6 | #ifndef BOOST_MAKE_DEFAULT_HPP | |
7 | #define BOOST_MAKE_DEFAULT_HPP | |
8 | ||
9 | namespace boost | |
10 | { | |
11 | /// @details A considerable number of libraries require an instance of a class | |
12 | /// provided (storage created and initialized). For example, | |
13 | /// @code | |
14 | /// Type result; | |
15 | /// ... | |
16 | /// istream >> result; | |
17 | /// @endcode | |
18 | /// In generic code that results in the Default Constructibility requirement imposed | |
19 | /// on every type 'Type' to be used with the respective code. Inevitably, that requirement | |
20 | /// a) either excludes all the classes that for various reasons do not meet that requirement or | |
21 | /// b) imposes certain (not necessarily desirable) design/implementation onto respective classes. | |
22 | /// | |
23 | /// Deployment of boost::make_default() eliminates the Default Constructibility requirement with | |
24 | /// @code | |
25 | /// Type result = boost::make_default<Type>(); | |
26 | /// ... | |
27 | /// istream >> result; | |
28 | /// @endcode | |
29 | /// Classes with no default constructor can now be included via a boost::make_default() specialization: | |
30 | /// @code | |
31 | /// namespace boost | |
32 | /// { | |
33 | /// template<> inline Type make_default<Type>() { return Type(parameters); } | |
34 | /// } | |
35 | /// @endcode | |
36 | ||
37 | template<typename T> T make_default() { return T(); } | |
38 | } | |
39 | ||
40 | #endif // BOOST_MAKE_DEFAULT_HPP |