00001 // Copyright (C) 2001, 2002, 2003 EPITA Research and Development Laboratory 00002 // 00003 // This file is part of the Olena Library. This library is free 00004 // software; you can redistribute it and/or modify it under the terms 00005 // of the GNU General Public License version 2 as published by the 00006 // Free Software Foundation. 00007 // 00008 // This library is distributed in the hope that it will be useful, 00009 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00010 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00011 // General Public License for more details. 00012 // 00013 // You should have received a copy of the GNU General Public License 00014 // along with this library; see the file COPYING. If not, write to 00015 // the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 00016 // Boston, MA 02110-1301, USA. 00017 // 00018 // As a special exception, you may use this file as part of a free 00019 // software library without restriction. Specifically, if other files 00020 // instantiate templates or use macros or inline functions from this 00021 // file, or you compile this file and link it with other files to 00022 // produce an executable, this file does not by itself cause the 00023 // resulting executable to be covered by the GNU General Public 00024 // License. This exception does not however invalidate any other 00025 // reasons why the executable file might be covered by the GNU General 00026 // Public License. 00027 00028 #ifndef NTG_CORE_TYPE_HH 00029 # define NTG_CORE_TYPE_HH 00030 00031 /* 00032 Utility classes. 00033 */ 00034 00035 namespace ntg 00036 { 00037 00038 // FIXME: see comments in ntg/core/value.hh about this duplicate of 00039 // metalic's code. 00040 00041 /*-------. 00042 | any<E> | 00043 `-------*/ 00044 00046 template <class E> 00047 class any 00048 { 00049 public: 00050 typedef E exact_type; 00051 00052 E& exact() { return static_cast<E&>(*this); } 00053 const E& exact() const { return static_cast<const E&>(*this); } 00054 }; 00055 00056 /*------------------. 00057 | any_(const_)class | 00058 `------------------*/ 00059 00060 /* 00061 Classes used to disambiguate overloading. They can store an 00062 instance of any object and restore it later. 00063 */ 00064 00065 template <class T> 00066 class any_class 00067 { 00068 public: 00069 any_class(T& t) : _target(t) {} 00070 00071 T& exact() { return _target; } 00072 00073 private: 00074 T& _target; 00075 }; 00076 00077 template <class T> 00078 class any_const_class 00079 { 00080 public: 00081 any_const_class(const T& t) : _target(t) {} 00082 00083 const T& exact() const { return _target; } 00084 00085 private: 00086 const T& _target; 00087 }; 00088 00089 } // end of ntg. 00090 00091 #endif // !NTG_CORE_TYPE_HH