Qore Programming Language  1.7.0
QoreNullNode.h
Go to the documentation of this file.
1 /* -*- mode: c++; indent-tabs-mode: nil -*- */
2 /*
3  QoreNullNode.h
4 
5  Qore Programming Language
6 
7  Copyright (C) 2003 - 2022 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 
43 
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 
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
static bool is_null(const AbstractQoreNode *n)
use this function to test for NULL
Definition: QoreNullNode.h:129
DLLEXPORT QoreNullNode Null
the global and unique NULL value in Qore
The base class for all value and parse types in Qore expression trees.
Definition: AbstractQoreNode.h:57
DLLLOCAL qore_type_t getType() const
returns the data type
Definition: AbstractQoreNode.h:175
container for holding Qore-language exception information and also for registering a "thread_exit" ca...
Definition: ExceptionSink.h:48
Qore's SQL "NULL" parse tree/value type, not-referenced counted, not dynamically allocated.
Definition: QoreNullNode.h:50
static DLLLOCAL const char * getStaticTypeName()
returns the type name (useful in templates)
Definition: QoreNullNode.h:116
virtual DLLEXPORT bool is_equal_hard(const AbstractQoreNode *v, ExceptionSink *xsink) const
tests for equality without type conversions (hard compare)
virtual DLLLOCAL int parseInit(QoreValue &val, QoreParseContext &parse_context)
returns the type information
virtual DLLEXPORT QoreValue evalImpl(bool &needs_deref, ExceptionSink *xsink) const
this function is never called for this type
virtual DLLEXPORT int getAsString(QoreString &str, int foff, class ExceptionSink *xsink) const
concatenate "<NULL>" to an existing QoreString
static DLLLOCAL qore_type_t getStaticTypeCode()
returns the type code (useful in templates)
Definition: QoreNullNode.h:121
virtual DLLEXPORT const char * getTypeName() const
returns the type name as a c string
virtual DLLEXPORT bool is_equal_soft(const AbstractQoreNode *v, ExceptionSink *xsink) const
tests for equality with possible type conversion (soft compare)
Qore's string type supported by the QoreEncoding class.
Definition: QoreString.h:93
virtual DLLEXPORT QoreValue evalImpl(bool &needs_deref, ExceptionSink *xsink) const
should never be called for value types
this class is for value types that will exists only once in the Qore library, reference counting is d...
Definition: AbstractQoreNode.h:389
int16_t qore_type_t
used to identify unique Qore data and parse types (descendents of AbstractQoreNode)
Definition: common.h:70
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
const qore_type_t NT_NULL
type value for QoreNullNode
Definition: node_types.h:48
The main value class in Qore, designed to be passed by value.
Definition: QoreValue.h:275