QoreNullNode.h

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/* -*- mode: c++; indent-tabs-mode: nil -*- */
/*
    QoreNullNode.h
 
    Qore Programming Language
 
    Copyright (C) 2003 - 2022 Qore Technologies, s.r.o.
 
    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following conditions:
 
    The above copyright notice and this permission notice shall be included in
    all copies or substantial portions of the Software.
 
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
    DEALINGS IN THE SOFTWARE.
 
    Note that the Qore library is released under a choice of three open-source
    licenses: MIT (as above), LGPL 2+, or GPL 2+; see README-LICENSE for more
    information.
*/
 
#ifndef _QORE_QORENULLNODE_H
 
#define _QORE_QORENULLNODE_H
 
#include <qore/AbstractQoreNode.h>
 
 
class QoreNullNode : public UniqueValueQoreNode {
private:
    DLLLOCAL virtual bool getAsBoolImpl() const;
 
    DLLLOCAL virtual int getAsIntImpl() const;
 
    DLLLOCAL virtual int64 getAsBigIntImpl() const;
 
    DLLLOCAL virtual double getAsFloatImpl() const;
 
protected:
 
    using SimpleValueQoreNode::evalImpl;
    DLLLOCAL QoreValue evalImpl(bool& needs_deref, 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 int parseInit(QoreValue& val, QoreParseContext& parse_context);
 
    DLLLOCAL static const char *getStaticTypeName() {
        return "NULL";
    }
 
    DLLLOCAL static qore_type_t getStaticTypeCode() {
        return NT_NULL;
    }
 
    static const qore_type_t TYPE = NT_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