include/qore/QoreNullNode.h (4311)

Go to the documentation of this file.

/* -*- mode: c++; indent-tabs-mode: nil -*- */
/*
  QoreNullNode.h
  
  Qore Programming Language

  Copyright 2003 - 2011 David Nichols

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

#ifndef _QORE_QORENULLNODE_H

#define _QORE_QORENULLNODE_H

#include <qore/AbstractQoreNode.h>



class QoreNullNode : public UniqueValueQoreNode {
   protected:

      using SimpleValueQoreNode::evalImpl;
      DLLLOCAL AbstractQoreNode *evalImpl(class ExceptionSink *xsink) const;

   public:
      DLLEXPORT QoreNullNode();

      DLLEXPORT virtual ~QoreNullNode();


      DLLEXPORT virtual int getAsString(QoreString &str, int foff, class ExceptionSink *xsink) const;


      DLLEXPORT virtual QoreString *getAsString(bool &del, int foff, class ExceptionSink *xsink) const;


      DLLEXPORT virtual bool is_equal_soft(const AbstractQoreNode *v, ExceptionSink *xsink) const;


      DLLEXPORT virtual bool is_equal_hard(const AbstractQoreNode *v, ExceptionSink *xsink) const;

      DLLEXPORT virtual const char *getTypeName() const;

      DLLLOCAL virtual AbstractQoreNode *parseInit(LocalVar *oflag, int pflag, int &lvids, const QoreTypeInfo *&typeInfo);

      DLLLOCAL static const char *getStaticTypeName() {
         return "NULL";
      }
};

static inline bool is_null(const AbstractQoreNode *n)
{
   // this is faster than a dynamic_cast<const QoreNullNode *> operation
   return n && n->getType() == NT_NULL;
}

DLLEXPORT extern QoreNullNode Null;

static inline QoreNullNode *null()
{
   return &Null;
}

#endif