1 /**************************************************************************** 2 ** 3 ** Copyright (C) 2016 The Qt Company Ltd. 4 ** Contact: https://www.qt.io/licensing/ 5 ** 6 ** This file is part of the QtXmlPatterns module of the Qt Toolkit. 7 ** 8 ** $QT_BEGIN_LICENSE:LGPL$ 9 ** Commercial License Usage 10 ** Licensees holding valid commercial Qt licenses may use this file in 11 ** accordance with the commercial license agreement provided with the 12 ** Software or, alternatively, in accordance with the terms contained in 13 ** a written agreement between you and The Qt Company. For licensing terms 14 ** and conditions see https://www.qt.io/terms-conditions. For further 15 ** information use the contact form at https://www.qt.io/contact-us. 16 ** 17 ** GNU Lesser General Public License Usage 18 ** Alternatively, this file may be used under the terms of the GNU Lesser 19 ** General Public License version 3 as published by the Free Software 20 ** Foundation and appearing in the file LICENSE.LGPL3 included in the 21 ** packaging of this file. Please review the following information to 22 ** ensure the GNU Lesser General Public License version 3 requirements 23 ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. 24 ** 25 ** GNU General Public License Usage 26 ** Alternatively, this file may be used under the terms of the GNU 27 ** General Public License version 2.0 or (at your option) the GNU General 28 ** Public license version 3 or any later version approved by the KDE Free 29 ** Qt Foundation. The licenses are as published by the Free Software 30 ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 31 ** included in the packaging of this file. Please review the following 32 ** information to ensure the GNU General Public License requirements will 33 ** be met: https://www.gnu.org/licenses/gpl-2.0.html and 34 ** https://www.gnu.org/licenses/gpl-3.0.html. 35 ** 36 ** $QT_END_LICENSE$ 37 ** 38 ****************************************************************************/ 39 40 // 41 // W A R N I N G 42 // ------------- 43 // 44 // This file is not part of the Qt API. It exists purely as an 45 // implementation detail. This header file may change from version to 46 // version without notice, or even be removed. 47 // 48 // We mean it. 49 50 #ifndef Patternist_EmptySequence_H 51 #define Patternist_EmptySequence_H 52 53 #include <private/qemptycontainer_p.h> 54 55 QT_BEGIN_NAMESPACE 56 57 namespace QPatternist 58 { 59 /** 60 * @short Implements the value instance of empty sequence: <tt>()</tt>. 61 * 62 * @author Frans Englich <frans.englich@nokia.com> 63 * @ingroup Patternist_xdm 64 */ 65 class EmptySequence : public EmptyContainer 66 { 67 public: 68 /** 69 * @short Creates an EmptySequence that is a replacement for @p 70 * replacementFor. 71 * 72 * @see EmptySequence() 73 */ 74 static Expression::Ptr create(const Expression *const replacementFor, 75 const StaticContext::Ptr &context); 76 77 78 /** 79 * @short Creates an instance of EmptySequence. 80 * 81 * @note In most cases create() should be used, since it takes care of 82 * adjusting source location annotations. 83 * 84 * @see create() 85 */ EmptySequence()86 inline EmptySequence() 87 { 88 } 89 90 virtual QString stringValue() const; 91 92 /** 93 * @returns always an empty iterator, an instance of EmptyIterator. 94 */ 95 virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &) const; 96 97 /** 98 * @returns always @c null. 99 */ 100 virtual Item evaluateSingleton(const DynamicContext::Ptr &) const; 101 102 /** 103 * Does nothing. 104 */ 105 virtual void evaluateToSequenceReceiver(const DynamicContext::Ptr &) const; 106 107 /** 108 * @returns always @c false. 109 */ 110 virtual bool evaluateEBV(const DynamicContext::Ptr &context) const; 111 112 /** 113 * @returns always CommonSequenceTypes::Empty 114 */ 115 virtual ItemType::Ptr type() const; 116 117 /** 118 * @returns always CommonSequenceTypes::Empty 119 */ 120 virtual SequenceType::Ptr staticType() const; 121 122 virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const; 123 virtual ID id() const; 124 virtual Properties properties() const; 125 }; 126 } 127 128 QT_END_NAMESPACE 129 130 #endif 131