Data Objects: null.h Source File

00001 /****
00002  Hierarchical Data Objects
00003  Copyright (C) 2005-2010 Werner Van Belle
00004  http://flow.yellowcouch.org/data/
00005 
00006  This program is free software; you can redistribute it and/or modify
00007  it under the terms of the GNU General Public License as published by
00008  the Free Software Foundation; either version 2 of the License, or
00009  (at your option) any later version.
00010  
00011  This program is distributed in the hope that it will be useful,
00012  but WITHOUT ANY WARRANTY; without even the implied warranty of
00013  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014  GNU General Public License for more details.
00015 
00016  You should have received a copy of the GNU General Public License
00017  along with this program; if not, write to the Free Software
00018  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
00019 ****/
00020 #ifndef __loaded__null_h__
00021 #define __loaded__null_h__
00022 using namespace std;
00023 #line 1 "null.h++"
00024 #include "data.h"
00025 
00026 //---------------------------------------------------------------
00027 //                            Null
00028 //---------------------------------------------------------------
00029 class Null: public DataClass
00030 {
00031  private:
00032   void crash() const;
00033  protected:
00034   virtual QString type_name() const 
00035     {
00036       return "Null"; 
00037     };
00038   virtual DataClass* shallow_copy() const 
00039     {
00040       return new Null();
00041     };
00042   virtual void visit(DataVisitor&) 
00043     {
00044       crash(); 
00045     };
00046  public:
00047   Null() 
00048     {
00049     };
00050 };
00051 #endif // __loaded__null_h__