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QoreNullNode.h
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1 /* -*- mode: c++; indent-tabs-mode: nil -*- */
2 /*
3 QoreNullNode.h
4
5 Qore Programming Language
6
7 Copyright (C) 2003 - 2021 Qore Technologies, s.r.o.
8
9 Permission is hereby granted, free of charge, to any person obtaining a
10 copy of this software and associated documentation files (the "Software"),
11 to deal in the Software without restriction, including without limitation
12 the rights to use, copy, modify, merge, publish, distribute, sublicense,
13 and/or sell copies of the Software, and to permit persons to whom the
14 Software is furnished to do so, subject to the following conditions:
15
16 The above copyright notice and this permission notice shall be included in
17 all copies or substantial portions of the Software.
18
19 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
22 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
24 FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
25 DEALINGS IN THE SOFTWARE.
26
27 Note that the Qore library is released under a choice of three open-source
28 licenses: MIT (as above), LGPL 2+, or GPL 2+; see README-LICENSE for more
29 information.
30 */
31
32 #ifndef _QORE_QORENULLNODE_H
33
34 #define _QORE_QORENULLNODE_H
35
36 #include <qore/AbstractQoreNode.h>
37
42
50 class QoreNullNode : public UniqueValueQoreNode {
51 private:
53 DLLLOCAL virtual bool getAsBoolImpl() const;
54
56 DLLLOCAL virtual int getAsIntImpl() const;
57
59 DLLLOCAL virtual int64 getAsBigIntImpl() const;
60
62 DLLLOCAL virtual double getAsFloatImpl() const;
63
64 protected:
66
68 using SimpleValueQoreNode::evalImpl;
69 DLLLOCAL QoreValue evalImpl(bool& needs_deref, ExceptionSink* xsink) const;
70
71 public:
72 DLLEXPORT QoreNullNode();
73
74 DLLEXPORT virtual ~QoreNullNode();
75
77
83 DLLEXPORT virtual int getAsString(QoreString &str, int foff, class ExceptionSink *xsink) const;
84
86
93 DLLEXPORT virtual QoreString *getAsString(bool &del, int foff, class ExceptionSink *xsink) const;
94
96
100 DLLEXPORT virtual bool is_equal_soft(const AbstractQoreNode *v, ExceptionSink *xsink) const;
101
103
107 DLLEXPORT virtual bool is_equal_hard(const AbstractQoreNode *v, ExceptionSink *xsink) const;
108
110 DLLEXPORT virtual const char *getTypeName() const;
111
113 DLLLOCAL virtual int parseInit(QoreValue& val, QoreParseContext& parse_context);
114
116 DLLLOCAL static const char *getStaticTypeName() {
117 return "NULL";
118 }
119
121 DLLLOCAL static qore_type_t getStaticTypeCode() {
122 return NT_NULL;
123 }
124
125 static const qore_type_t TYPE = NT_NULL;
126 };
127
129 static inline bool is_null(const AbstractQoreNode *n) {
130 // this is faster than a dynamic_cast<const QoreNullNode *> operation
131 return n && n->getType() == NT_NULL;
132 }
133
135 DLLEXPORT extern QoreNullNode Null;
136
138 static inline QoreNullNode *null() {
139 return &Null;
140 }
141
142 #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