casacore
TaQLNodeResult.h
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1//# TaQLNodeResult.h: Classes holding the result of a node tree visit
2//# Copyright (C) 2005
3//# Associated Universities, Inc. Washington DC, USA.
4//#
5//# This library is free software; you can redistribute it and/or modify it
6//# under the terms of the GNU Library General Public License as published by
7//# the Free Software Foundation; either version 2 of the License, or (at your
8//# option) any later version.
9//#
10//# This library is distributed in the hope that it will be useful, but WITHOUT
11//# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12//# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
13//# License for more details.
14//#
15//# You should have received a copy of the GNU Library General Public License
16//# along with this library; if not, write to the Free Software Foundation,
17//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
18//#
19//# Correspondence concerning AIPS++ should be addressed as follows:
20//# Internet email: aips2-request@nrao.edu.
21//# Postal address: AIPS++ Project Office
22//# National Radio Astronomy Observatory
23//# 520 Edgemont Road
24//# Charlottesville, VA 22903-2475 USA
25//#
26//# $Id$
27
28#ifndef TABLES_TAQLNODERESULT_H
29#define TABLES_TAQLNODERESULT_H
30
31//# Includes
32#include <casacore/casa/aips.h>
33
34namespace casacore { //# NAMESPACE CASACORE - BEGIN
35
36// <summary>
37// Abstract base class to hold the result of a visit to the node tree.
38// </summary>
39
40// <use visibility=local>
41
42// <reviewed reviewer="" date="" tests="tTableGram">
43// </reviewed>
44
45// <prerequisite>
46//# Classes you should understand before using this one.
47// <li> <linkto class=TaQLNodeVisitor>TaQLNodeVisitor</linkto>
48// <li> Note 199 describing
49// <a href="../notes/199.html">
50// TaQL</a>
51// </prerequisite>
52
53// <synopsis>
54// TaQLNodeResultRep is the abstract base class for classes holding
55// values filled by visitors to the raw TaQL parse tree. Visitors are
56// classes derived from <linkto class=TaQLNodeVisitor>TaQLNodeVisitor</linkto>
57// which traverse the parse tree.
58// TaQLNodeResultRep is the counted referenced letter class in the envelope
59// class <linkto class=TaQLNodeResult>TaQLNodeResult</linkto>.
60// </synopsis>
61
63{
64public:
65 // Default constructor clears the reference count.
66 // The count is updated by functions link and unlink.
68 : itsCount(0) {}
69
70 // Destructor.
72
73 // Increment the reference count.
75 {
76 if (rep) ++rep->itsCount;
77 return rep;
78 }
79
80 // Decrement the reference count.
81 // Delete the letter if no more references.
82 static void unlink (TaQLNodeResultRep* rep)
83 {
84 if (rep && --rep->itsCount == 0) delete rep;
85 }
86
87private:
88 // Letter objects cannot be copied.
89 // <group>
92 // </group>
93
95};
96
97
98// <summary>
99// Envelope class to hold the result of a visit to the node tree.
100// </summary>
101
102// <use visibility=local>
103
104// <reviewed reviewer="" date="" tests="tTableGram">
105// </reviewed>
106
107// <prerequisite>
108//# Classes you should understand before using this one.
109// <li> <linkto class=TaQLNodeVisitor>TaQLNodeVisitor</linkto>
110// <li> Note 199 describing
111// <a href="../notes/199.html">
112// TaQL</a>
113// </prerequisite>
114
115// <synopsis>
116// TaQLNodeResult is the envelope class for classes holding
117// values filled by visitors to the raw TaQL parse tree. Visitors are
118// classes derived from <linkto class=TaQLNodeVisitor>TaQLNodeVisitor</linkto>
119// which traverse the parse tree.
120// The counted referenced letter base class for the envelope is
121// class <linkto class=TaQLNodeResultRep>TaQLNodeResultRep</linkto>.
122// </synopsis>
124{
125public:
126 // Default constructor has no letter.
128 : itsRep(0) {}
129
130 // Take the given letter and increment its reference count.
133
134 // Copy constructor (reference semantics).
137
138 // Assignment (reference semantics).
140 { if (this != &that) {
143 }
144 return *this;
145 }
146
147 // Destructor decrements the reference count.
148 // The letter is deleted if no more references.
151
152 // Does the envelope hold a letter?
153 Bool isValid() const
154 { return itsRep; }
155
156private:
158
159public:
160 // Get the actual underlying object.
162 { return itsRep; }
163};
164
165} //# NAMESPACE CASACORE - END
166
167#endif
TaQLNodeResultRep & operator=(const TaQLNodeResultRep &)
static void unlink(TaQLNodeResultRep *rep)
Decrement the reference count.
TaQLNodeResultRep()
Default constructor clears the reference count.
virtual ~TaQLNodeResultRep()
Destructor.
static TaQLNodeResultRep * link(TaQLNodeResultRep *rep)
Increment the reference count.
TaQLNodeResultRep(const TaQLNodeResultRep &)
Letter objects cannot be copied.
Envelope class to hold the result of a visit to the node tree.
TaQLNodeResult(const TaQLNodeResult &that)
Copy constructor (reference semantics).
~TaQLNodeResult()
Destructor decrements the reference count.
TaQLNodeResult(TaQLNodeResultRep *rep)
Take the given letter and increment its reference count.
TaQLNodeResultRep * itsRep
TaQLNodeResult & operator=(const TaQLNodeResult &that)
Assignment (reference semantics).
const TaQLNodeResultRep * getRep() const
Get the actual underlying object.
Bool isValid() const
Does the envelope hold a letter?
TaQLNodeResult()
Default constructor has no letter.
this file contains all the compiler specific defines
Definition: mainpage.dox:28
bool Bool
Define the standard types used by Casacore.
Definition: aipstype.h:42