00001 /* -*- mode: c++; indent-tabs-mode: nil -*- */ 00002 /* 00003 QoreNullNode.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_QORENULLNODE_H 00025 00026 #define _QORE_QORENULLNODE_H 00027 00028 #include <qore/AbstractQoreNode.h> 00029 00034 00035 00042 class QoreNullNode : public UniqueValueQoreNode { 00043 protected: 00045 00047 using SimpleValueQoreNode::evalImpl; 00048 DLLLOCAL AbstractQoreNode *evalImpl(class ExceptionSink *xsink) const; 00049 00050 public: 00051 DLLEXPORT QoreNullNode(); 00052 00053 DLLEXPORT virtual ~QoreNullNode(); 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 00092 DLLLOCAL virtual AbstractQoreNode *parseInit(LocalVar *oflag, int pflag, int &lvids, const QoreTypeInfo *&typeInfo); 00093 00094 DLLLOCAL static const char *getStaticTypeName() { 00095 return "NULL"; 00096 } 00097 }; 00098 00100 static inline bool is_null(const AbstractQoreNode *n) 00101 { 00102 // this is faster than a dynamic_cast<const QoreNullNode *> operation 00103 return n && n->getType() == NT_NULL; 00104 } 00105 00107 DLLEXPORT extern QoreNullNode Null; 00108 00110 static inline QoreNullNode *null() 00111 { 00112 return &Null; 00113 } 00114 00115 #endif