00001 // Copyright (C) 2007, 2009 EPITA Research and Development Laboratory (LRDE) 00002 // 00003 // This file is part of Olena. 00004 // 00005 // Olena is free software: you can redistribute it and/or modify it under 00006 // the terms of the GNU General Public License as published by the Free 00007 // Software Foundation, version 2 of the License. 00008 // 00009 // Olena is distributed in the hope that it will be useful, 00010 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00011 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00012 // General Public License for more details. 00013 // 00014 // You should have received a copy of the GNU General Public License 00015 // along with Olena. If not, see <http://www.gnu.org/licenses/>. 00016 // 00017 // As a special exception, you may use this file as part of a free 00018 // software project without restriction. Specifically, if other files 00019 // instantiate templates or use macros or inline functions from this 00020 // file, or you compile this file and link it with other files to produce 00021 // an executable, this file does not by itself cause the resulting 00022 // executable to be covered by the GNU General Public License. This 00023 // exception does not however invalidate any other reasons why the 00024 // executable file might be covered by the GNU General Public License. 00025 00026 #ifndef MLN_UTIL_NIL_HH 00027 # define MLN_UTIL_NIL_HH 00028 00032 00033 # include <mln/core/concept/object.hh> 00034 00035 00036 namespace mln 00037 { 00038 00039 namespace util 00040 { 00041 00045 // 00046 struct nil : public Object< nil > 00047 { 00048 nil(); 00049 00050 // Just like util::eat: 00051 00052 template <typename T> 00053 nil(const T&); 00054 00055 template <typename T> 00056 nil& operator=(const T&); 00057 00058 // Just like util::ignore: 00059 00060 template <typename T> 00061 operator T() const; 00062 }; 00063 00064 # ifndef MLN_INCLUDE_ONLY 00065 00066 // nil 00067 00068 inline 00069 nil::nil() 00070 { 00071 } 00072 00073 template <typename T> 00074 inline 00075 nil::nil(const T&) 00076 { 00077 } 00078 00079 template <typename T> 00080 inline 00081 nil& 00082 nil::operator=(const T&) 00083 { 00084 return *this; 00085 } 00086 00087 template <typename T> 00088 inline 00089 nil::operator T() const 00090 { 00091 return T(); 00092 } 00093 00094 # endif // ! MLN_INCLUDE_ONLY 00095 00096 } // end of namespace mln::util 00097 00098 } // end of namespace mln 00099 00100 00101 #endif // ! MLN_UTIL_NIL_HH
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