QoreNullNode.h
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/* -*- mode: c++; indent-tabs-mode: nil -*- */
/*
QoreNullNode.h
Qore Programming Language
Copyright (C) 2003 - 2021 Qore Technologies, s.r.o.
Permission is hereby granted, free of charge, to any person obtaining a
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DEALINGS IN THE SOFTWARE.
Note that the Qore library is released under a choice of three open-source
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*/
#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
QoreNullNode::is_equal_hard
virtual DLLEXPORT bool is_equal_hard(const AbstractQoreNode *v, ExceptionSink *xsink) const
tests for equality without type conversions (hard compare)
AbstractQoreNode::getType
DLLLOCAL qore_type_t getType() const
returns the data type
Definition: AbstractQoreNode.h:175
QoreNullNode::getStaticTypeCode
static DLLLOCAL qore_type_t getStaticTypeCode()
returns the type code (useful in templates)
Definition: QoreNullNode.h:121
Null
DLLEXPORT QoreNullNode Null
the global and unique NULL value in Qore
is_null
static bool is_null(const AbstractQoreNode *n)
use this function to test for NULL
Definition: QoreNullNode.h:129
QoreNullNode::is_equal_soft
virtual DLLEXPORT bool is_equal_soft(const AbstractQoreNode *v, ExceptionSink *xsink) const
tests for equality with possible type conversion (soft compare)
QoreNullNode::getStaticTypeName
static DLLLOCAL const char * getStaticTypeName()
returns the type name (useful in templates)
Definition: QoreNullNode.h:116
QoreNullNode::getAsString
virtual DLLEXPORT int getAsString(QoreString &str, int foff, class ExceptionSink *xsink) const
concatenate "<NULL>" to an existing QoreString
AbstractQoreNode
The base class for all value and parse types in Qore expression trees.
Definition: AbstractQoreNode.h:57
null
static QoreNullNode * null()
returns a pointer to Null
Definition: QoreNullNode.h:138
NT_NULL
const qore_type_t NT_NULL
type value for QoreNullNode
Definition: node_types.h:48
QoreString
Qore&#39;s string type supported by the QoreEncoding class.
Definition: QoreString.h:81
UniqueValueQoreNode
this class is for value types that will exists only once in the Qore library, reference counting is d...
Definition: AbstractQoreNode.h:389
QoreNullNode
Qore&#39;s SQL "NULL" parse tree/value type, not-referenced counted, not dynamically allocated.
Definition: QoreNullNode.h:50
QoreValue
The main value class in Qore, designed to be passed by value.
Definition: QoreValue.h:267
ExceptionSink
container for holding Qore-language exception information and also for registering a "thread_exit" ca...
Definition: ExceptionSink.h:48
int64
long long int64
64bit integer type, cannot use int64_t here since it breaks the API on some 64-bit systems due to equ...
Definition: common.h:260
SimpleValueQoreNode::evalImpl
virtual DLLEXPORT QoreValue evalImpl(bool &needs_deref, ExceptionSink *xsink) const
should never be called for value types
qore_type_t
int16_t qore_type_t
used to identify unique Qore data and parse types (descendents of AbstractQoreNode) ...
Definition: common.h:70
QoreNullNode::parseInit
virtual DLLLOCAL int parseInit(QoreValue &val, QoreParseContext &parse_context)
returns the type information
QoreNullNode::evalImpl
DLLLOCAL QoreValue evalImpl(bool &needs_deref, ExceptionSink *xsink) const
should never be called for value types
QoreNullNode::getTypeName
virtual DLLEXPORT const char * getTypeName() const
returns the type name as a c string