00001 /* 00002 QoreNothingNode.h 00003 00004 Qore Programming Language 00005 00006 Copyright 2003 - 2009 David Nichols 00007 00008 This library is free software; you can redistribute it and/or 00009 modify it under the terms of the GNU Lesser General Public 00010 License as published by the Free Software Foundation; either 00011 version 2.1 of the License, or (at your option) any later version. 00012 00013 This library is distributed in the hope that it will be useful, 00014 but WITHOUT ANY WARRANTY; without even the implied warranty of 00015 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00016 Lesser General Public License for more details. 00017 00018 You should have received a copy of the GNU Lesser General Public 00019 License along with this library; if not, write to the Free Software 00020 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 00021 */ 00022 00023 #ifndef _QORE_QORENOTHINGNODE_H 00024 00025 #define _QORE_QORENOTHINGNODE_H 00026 00027 #include <qore/AbstractQoreNode.h> 00028 00033 00034 00042 class QoreNothingNode : public UniqueValueQoreNode 00043 { 00044 protected: 00046 00048 DLLLOCAL AbstractQoreNode *evalImpl(class ExceptionSink *xsink) const; 00049 00050 public: 00051 DLLEXPORT QoreNothingNode(); 00052 00053 DLLEXPORT virtual ~QoreNothingNode(); 00054 00056 00062 DLLEXPORT virtual int getAsString(QoreString &str, int foff, class ExceptionSink *xsink) const; 00063 00065 00072 DLLEXPORT virtual QoreString *getAsString(bool &del, int foff, class ExceptionSink *xsink) const; 00073 00075 00079 DLLEXPORT virtual bool is_equal_soft(const AbstractQoreNode *v, ExceptionSink *xsink) const; 00080 00082 00086 DLLEXPORT virtual bool is_equal_hard(const AbstractQoreNode *v, ExceptionSink *xsink) const; 00087 00089 DLLEXPORT virtual const char *getTypeName() const; 00090 00091 DLLLOCAL static const char *getStaticTypeName() 00092 { 00093 return "nothing"; 00094 } 00095 }; 00096 00098 DLLEXPORT extern QoreNothingNode Nothing; 00099 00101 static inline QoreNothingNode *nothing() 00102 { 00103 return &Nothing; 00104 } 00105 00106 #endif