| 1 | /// @file |
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| 2 | // Copyright (c) 2009-2014 Vladimir Batov. |
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| 3 | // Use, modification and distribution are subject to the Boost Software License, |
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| 4 | // Version 1.0. See http://www.boost.org/LICENSE_1_0.txt. |
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| 5 | |
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| 6 | #ifndef BOOST_MAKE_DEFAULT_HPP |
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| 7 | #define BOOST_MAKE_DEFAULT_HPP |
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| 8 | |
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| 9 | namespace boost |
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| 10 | { |
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| 11 | /// @details A considerable number of libraries require an instance of a class |
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| 12 | /// provided (storage created and initialized). For example, |
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| 13 | /// @code |
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| 14 | /// Type result; |
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| 15 | /// ... |
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| 16 | /// istream >> result; |
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| 17 | /// @endcode |
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| 18 | /// In generic code that results in the Default Constructibility requirement imposed |
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| 19 | /// on every type 'Type' to be used with the respective code. Inevitably, that requirement |
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| 20 | /// a) either excludes all the classes that for various reasons do not meet that requirement or |
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| 21 | /// b) imposes certain (not necessarily desirable) design/implementation onto respective classes. |
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| 22 | /// |
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| 23 | /// Deployment of boost::make_default() eliminates the Default Constructibility requirement with |
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| 24 | /// @code |
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| 25 | /// Type result = boost::make_default<Type>(); |
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| 26 | /// ... |
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| 27 | /// istream >> result; |
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| 28 | /// @endcode |
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| 29 | /// Classes with no default constructor can now be included via a boost::make_default() specialization: |
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| 30 | /// @code |
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| 31 | /// namespace boost |
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| 32 | /// { |
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| 33 | /// template<> inline Type make_default<Type>() { return Type(parameters); } |
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| 34 | /// } |
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| 35 | /// @endcode |
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| 36 | |
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| 37 | template<typename T> T make_default() { return T(); } |
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| 38 | } |
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| 39 | |
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| 40 | #endif // BOOST_MAKE_DEFAULT_HPP |
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| 41 | |
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