00001 // Copyright (C) 2007, 2008, 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_LITERAL_ZERO_HH 00027 # define MLN_LITERAL_ZERO_HH 00028 00034 00035 # include <mln/core/concept/literal.hh> 00036 # include <mln/metal/converts_to.hh> 00037 00038 00039 namespace mln 00040 { 00041 00042 namespace literal 00043 { 00044 00046 struct zero_t : public Literal<zero_t> 00047 { 00048 // FIXME: (for the record) Add "friend class Literal<zero_t>;" and a protected ctor. 00049 00050 template <typename T> 00051 operator const T () const; 00052 }; 00053 00055 extern const zero_t& zero; 00056 00057 # ifndef MLN_INCLUDE_ONLY 00058 00059 template <typename T> 00060 inline 00061 zero_t::operator const T () const 00062 { 00063 mlc_converts_to(int, T)::check(); 00064 return 0; 00065 } 00066 00067 # ifndef MLN_WO_GLOBAL_VARS 00068 00069 const zero_t& zero = zero_t(); 00070 00071 # endif // !MLN_GLOBAL_VARS 00072 00073 # endif // ! MLN_INCLUDE_ONLY 00074 00075 } // end of namespace mln::literal 00076 00077 } // end of namespace mln 00078 00079 00080 #endif // ! MLN_LITERAL_ZERO_HH
1.7.1