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1 /**************************************************************************** |
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2 ** |
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3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). |
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4 ** All rights reserved. |
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5 ** Contact: Nokia Corporation (qt-info@nokia.com) |
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6 ** |
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7 ** This file is part of the QtXmlPatterns module of the Qt Toolkit. |
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8 ** |
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9 ** $QT_BEGIN_LICENSE:LGPL$ |
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10 ** No Commercial Usage |
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11 ** This file contains pre-release code and may not be distributed. |
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12 ** You may use this file in accordance with the terms and conditions |
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13 ** contained in the Technology Preview License Agreement accompanying |
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14 ** this package. |
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15 ** |
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16 ** GNU Lesser General Public License Usage |
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17 ** Alternatively, this file may be used under the terms of the GNU Lesser |
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18 ** General Public License version 2.1 as published by the Free Software |
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19 ** Foundation and appearing in the file LICENSE.LGPL included in the |
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20 ** packaging of this file. Please review the following information to |
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21 ** ensure the GNU Lesser General Public License version 2.1 requirements |
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22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. |
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23 ** |
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24 ** In addition, as a special exception, Nokia gives you certain additional |
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25 ** rights. These rights are described in the Nokia Qt LGPL Exception |
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26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. |
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27 ** |
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28 ** If you have questions regarding the use of this file, please contact |
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29 ** Nokia at qt-info@nokia.com. |
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30 ** |
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31 ** |
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32 ** |
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33 ** |
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34 ** |
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35 ** |
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36 ** |
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37 ** |
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38 ** $QT_END_LICENSE$ |
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39 ** |
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40 ****************************************************************************/ |
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41 |
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42 // |
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43 // W A R N I N G |
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44 // ------------- |
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45 // |
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46 // This file is not part of the Qt API. It exists purely as an |
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47 // implementation detail. This header file may change from version to |
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48 // version without notice, or even be removed. |
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49 // |
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50 // We mean it. |
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51 |
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52 #ifndef Patternist_EmptySequence_H |
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53 #define Patternist_EmptySequence_H |
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54 |
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55 #include "qemptycontainer_p.h" |
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56 |
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57 QT_BEGIN_HEADER |
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58 |
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59 QT_BEGIN_NAMESPACE |
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60 |
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61 namespace QPatternist |
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62 { |
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63 /** |
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64 * @short Implements the value instance of empty sequence: <tt>()</tt>. |
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65 * |
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66 * @author Frans Englich <frans.englich@nokia.com> |
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67 * @ingroup Patternist_xdm |
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68 */ |
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69 class EmptySequence : public EmptyContainer |
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70 { |
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71 public: |
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72 /** |
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73 * @short Creates an EmptySequence that is a replacement for @p |
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74 * replacementFor. |
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75 * |
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76 * @see EmptySequence() |
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77 */ |
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78 static Expression::Ptr create(const Expression *const replacementFor, |
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79 const StaticContext::Ptr &context); |
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80 |
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81 |
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82 /** |
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83 * @short Creates an instance of EmptySequence. |
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84 * |
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85 * @note In most cases create() should be used, since it takes care of |
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86 * adjusting source location annotations. |
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87 * |
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88 * @see create() |
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89 */ |
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90 inline EmptySequence() |
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91 { |
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92 } |
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93 |
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94 virtual QString stringValue() const; |
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95 |
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96 /** |
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97 * @returns always an empty iterator, an instance of EmptyIterator. |
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98 */ |
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99 virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &) const; |
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100 |
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101 /** |
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102 * @returns always @c null. |
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103 */ |
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104 virtual Item evaluateSingleton(const DynamicContext::Ptr &) const; |
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105 |
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106 /** |
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107 * Does nothing. |
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108 */ |
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109 virtual void evaluateToSequenceReceiver(const DynamicContext::Ptr &) const; |
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110 |
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111 /** |
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112 * @returns always @c false. |
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113 */ |
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114 virtual bool evaluateEBV(const DynamicContext::Ptr &context) const; |
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115 |
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116 /** |
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117 * @returns always CommonSequenceTypes::Empty |
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118 */ |
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119 virtual ItemType::Ptr type() const; |
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120 |
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121 /** |
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122 * @returns always CommonSequenceTypes::Empty |
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123 */ |
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124 virtual SequenceType::Ptr staticType() const; |
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125 |
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126 virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const; |
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127 virtual ID id() const; |
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128 virtual Properties properties() const; |
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129 }; |
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130 } |
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131 |
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132 QT_END_NAMESPACE |
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133 |
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134 QT_END_HEADER |
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135 |
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136 #endif |