00001 /* -*- mode: c++; indent-tabs-mode: nil -*- */ 00002 /* 00003 QoreNothingNode.h 00004 00005 Qore Programming Language 00006 00007 Copyright 2003 - 2010 David Nichols 00008 00009 This library is free software; you can redistribute it and/or 00010 modify it under the terms of the GNU Lesser General Public 00011 License as published by the Free Software Foundation; either 00012 version 2.1 of the License, or (at your option) any later version. 00013 00014 This library is distributed in the hope that it will be useful, 00015 but WITHOUT ANY WARRANTY; without even the implied warranty of 00016 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00017 Lesser General Public License for more details. 00018 00019 You should have received a copy of the GNU Lesser General Public 00020 License along with this library; if not, write to the Free Software 00021 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 00022 */ 00023 00024 #ifndef _QORE_QORENOTHINGNODE_H 00025 00026 #define _QORE_QORENOTHINGNODE_H 00027 00028 #include <qore/AbstractQoreNode.h> 00029 00034 00035 00043 class QoreNothingNode : public UniqueValueQoreNode { 00044 protected: 00046 00048 using SimpleValueQoreNode::evalImpl; 00049 DLLLOCAL AbstractQoreNode *evalImpl(ExceptionSink *xsink) const; 00050 00051 public: 00052 DLLEXPORT QoreNothingNode(); 00053 00054 DLLEXPORT virtual ~QoreNothingNode(); 00055 00057 00063 DLLEXPORT virtual int getAsString(QoreString &str, int foff, class ExceptionSink *xsink) const; 00064 00066 00073 DLLEXPORT virtual QoreString *getAsString(bool &del, int foff, class ExceptionSink *xsink) const; 00074 00076 00080 DLLEXPORT virtual bool is_equal_soft(const AbstractQoreNode *v, ExceptionSink *xsink) const; 00081 00083 00087 DLLEXPORT virtual bool is_equal_hard(const AbstractQoreNode *v, ExceptionSink *xsink) const; 00088 00090 DLLEXPORT virtual const char *getTypeName() const; 00091 00093 DLLLOCAL virtual AbstractQoreNode *parseInit(LocalVar *oflag, int pflag, int &lvids, const QoreTypeInfo *&typeInfo); 00094 00095 DLLLOCAL static const char *getStaticTypeName() { 00096 return "nothing"; 00097 } 00098 }; 00099 00101 DLLEXPORT extern QoreNothingNode Nothing; 00102 00104 static inline QoreNothingNode *nothing() 00105 { 00106 return &Nothing; 00107 } 00108 00109 #endif