| 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 | ** Contact: Qt Software Information ([email protected])
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| 5 | **
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| 6 | ** This file is part of the QtXmlPatterns module of the Qt Toolkit.
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| 7 | **
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| 8 | ** $QT_BEGIN_LICENSE:LGPL$
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| 9 | ** Commercial Usage
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| 10 | ** Licensees holding valid Qt Commercial licenses may use this file in
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| 11 | ** accordance with the Qt Commercial License Agreement provided with the
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| 12 | ** Software or, alternatively, in accordance with the terms contained in
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| 13 | ** a written agreement between you and Nokia.
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| 14 | **
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| 15 | ** GNU Lesser General Public License Usage
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| 16 | ** Alternatively, this file may be used under the terms of the GNU Lesser
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| 17 | ** General Public License version 2.1 as published by the Free Software
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| 18 | ** Foundation and appearing in the file LICENSE.LGPL included in the
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| 19 | ** packaging of this file. Please review the following information to
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| 20 | ** ensure the GNU Lesser General Public License version 2.1 requirements
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| 21 | ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
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| 22 | **
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| 23 | ** In addition, as a special exception, Nokia gives you certain
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| 24 | ** additional rights. These rights are described in the Nokia Qt LGPL
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| 25 | ** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
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| 26 | ** package.
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| 27 | **
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| 28 | ** GNU General Public License Usage
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| 29 | ** Alternatively, this file may be used under the terms of the GNU
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| 30 | ** General Public License version 3.0 as published by the Free Software
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| 31 | ** Foundation and appearing in the file LICENSE.GPL included in the
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| 32 | ** packaging of this file. Please review the following information to
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| 33 | ** ensure the GNU General Public License version 3.0 requirements will be
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| 34 | ** met: http://www.gnu.org/copyleft/gpl.html.
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| 35 | **
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| 36 | ** If you are unsure which license is appropriate for your use, please
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| 37 | ** contact the sales department at [email protected].
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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_SequenceFNs_H
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| 53 | #define Patternist_SequenceFNs_H
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| 54 |
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| 55 | #include "qatomiccomparator_p.h"
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| 56 | #include "qcomparisonplatform_p.h"
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| 57 | #include "qliteral_p.h"
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| 58 | #include "qfunctioncall_p.h"
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| 59 |
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| 60 | /**
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| 61 | * @file
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| 62 | * @short Contains classes implementing the functions found in
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| 63 | * <a href="http://www.w3.org/TR/xpath-functions/#general-seq-funcs">XQuery 1.0 and
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| 64 | * XPath 2.0 Functions and Operators, 15.1 General Functions and Operators on Sequences</a>.
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| 65 | *
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| 66 | * @todo document that some functions have both eval funcs implented.
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| 67 | *
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| 68 | * @ingroup Patternist_functions
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| 69 | */
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| 70 |
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| 71 | QT_BEGIN_HEADER
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| 72 |
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| 73 | QT_BEGIN_NAMESPACE
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| 74 |
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| 75 | namespace QPatternist
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| 76 | {
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| 77 | /**
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| 78 | * @short Implements the function <tt>fn:boolean()</tt>.
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| 79 | *
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| 80 | * @see EBVExtractor
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| 81 | * @ingroup Patternist_functions
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| 82 | * @author Frans Englich <[email protected]>
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| 83 | */
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| 84 | class BooleanFN : public FunctionCall
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| 85 | {
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| 86 | public:
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| 87 | virtual bool evaluateEBV(const DynamicContext::Ptr &context) const;
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| 88 |
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| 89 | /**
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| 90 | * If @p reqType is CommonSequenceTypes::EBV, the type check of
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| 91 | * the operand is returned. Hence, this removes redundant calls
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| 92 | * to <tt>fn:boolean()</tt>.
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| 93 | */
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| 94 | virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
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| 95 | const SequenceType::Ptr &reqType);
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| 96 | };
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| 97 |
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| 98 | /**
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| 99 | * @short Implements the function <tt>fn:index-of()</tt>.
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| 100 | *
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| 101 | * @ingroup Patternist_functions
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| 102 | * @author Frans Englich <[email protected]>
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| 103 | */
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| 104 | class IndexOfFN : public FunctionCall,
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| 105 | public ComparisonPlatform<IndexOfFN, false>
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| 106 | {
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| 107 | public:
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| 108 | inline IndexOfFN() : ComparisonPlatform<IndexOfFN, false>()
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| 109 | {
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| 110 | }
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| 111 |
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| 112 | virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
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| 113 | virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
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| 114 | const SequenceType::Ptr &reqType);
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| 115 |
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| 116 | inline AtomicComparator::Operator operatorID() const
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| 117 | {
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| 118 | return AtomicComparator::OperatorEqual;
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| 119 | }
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| 120 | };
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| 121 |
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| 122 | /**
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| 123 | * @short Implements the functions <tt>fn:exists()</tt> and <tt>fn:empty()</tt>.
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| 124 | *
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| 125 | * Existence is a template value class. Appropriate implementations are achieved
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| 126 | * by instantiating it with either IDExistsFN or IDEmptyFN.
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| 127 | *
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| 128 | * @ingroup Patternist_functions
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| 129 | * @author Frans Englich <[email protected]>
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| 130 | */
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| 131 | template<const Expression::ID Id>
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| 132 | class Existence : public FunctionCall
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| 133 | {
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| 134 | public:
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| 135 | virtual bool evaluateEBV(const DynamicContext::Ptr &context) const
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| 136 | {
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| 137 | if(Id == IDExistsFN)
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| 138 | return !m_operands.first()->evaluateSequence(context)->isEmpty();
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| 139 | else
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| 140 | return m_operands.first()->evaluateSequence(context)->isEmpty();
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| 141 | }
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| 142 |
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| 143 | /**
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| 144 | * Attempts to rewrite to @c false or @c true by looking at the static
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| 145 | * cardinality of its operand.
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| 146 | */
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| 147 | virtual Expression::Ptr compress(const StaticContext::Ptr &context)
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| 148 | {
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| 149 | Q_ASSERT(Id == IDExistsFN || Id == IDEmptyFN);
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| 150 | const Expression::Ptr me(FunctionCall::compress(context));
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| 151 |
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| 152 | if(me != this)
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| 153 | return me;
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| 154 |
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| 155 | const Cardinality myCard((Id == IDExistsFN) ? Cardinality::oneOrMore() : Cardinality::empty());
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| 156 |
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| 157 | const Cardinality card(m_operands.first()->staticType()->cardinality());
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| 158 | if(myCard.isMatch(card))
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| 159 | { /* Since the dynamic type always is narrower than the static type or equal, and that the
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| 160 | static type is in scope, it means we will always be true. */
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| 161 | return wrapLiteral(CommonValues::BooleanTrue, context, this);
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| 162 | }
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| 163 | else
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| 164 | {
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| 165 | /* Is it even possible to hit? */
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| 166 | if(myCard.canMatch(card))
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| 167 | {
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| 168 | return me;
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| 169 | }
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| 170 | else
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| 171 | { /* We can never hit. */
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| 172 | return wrapLiteral(CommonValues::BooleanFalse, context, this);
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| 173 | }
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| 174 | }
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| 175 | }
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| 176 | };
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| 177 |
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| 178 | /**
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| 179 | * @short Implements the function <tt>fn:distinct-values()</tt>.
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| 180 | *
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| 181 | * @ingroup Patternist_functions
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| 182 | * @author Frans Englich <[email protected]>
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| 183 | */
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| 184 | class DistinctValuesFN : public FunctionCall,
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| 185 | public ComparisonPlatform<IndexOfFN, false>
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| 186 | {
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| 187 | public:
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| 188 | inline DistinctValuesFN() : ComparisonPlatform<IndexOfFN, false>()
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| 189 | {
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| 190 | }
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| 191 |
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| 192 | virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
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| 193 | /**
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| 194 | * Performs necessary type checks, but also implements the optimization
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| 195 | * of rewriting to its operand if the operand's cardinality is zero-or-one
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| 196 | * or exactly-one.
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| 197 | */
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| 198 | virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
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| 199 | const SequenceType::Ptr &reqType);
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| 200 | /**
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| 201 | * @returns a type whose item type is the type of the first operand, and
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| 202 | * a cardinality which is non-empty if the first operand's type is non-empty
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| 203 | * and allows exactly-one. The latter is needed for operands which has the
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| 204 | * cardinality 2+, since distinct-values possibly removes items from the
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| 205 | * source sequence.
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| 206 | */
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| 207 | virtual SequenceType::Ptr staticType() const;
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| 208 |
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| 209 | protected:
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| 210 | inline AtomicComparator::Operator operatorID() const
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| 211 | {
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| 212 | return AtomicComparator::OperatorEqual;
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| 213 | }
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| 214 | };
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| 215 |
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| 216 | /**
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| 217 | * @short Implements the function <tt>fn:insert-before()</tt>.
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| 218 | *
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| 219 | * @todo docs, explain why evaluateSequence and evaluateSingleton is implemented
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| 220 | *
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| 221 | * @ingroup Patternist_functions
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| 222 | * @author Frans Englich <[email protected]>
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| 223 | */
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| 224 | class InsertBeforeFN : public FunctionCall
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| 225 | {
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| 226 | public:
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| 227 | virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
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| 228 | virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
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| 229 |
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| 230 | /**
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| 231 | * Implements the static enferences rules. The function's static item type
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| 232 | * is the union type of the first and third argument, and the cardinality is
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| 233 | * the cardinalities of the two operands added together. For example,
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| 234 | * insert-before((1, "str"), 1, xs:double(0)) has the static type xs:anyAtomicType+.
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| 235 | *
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| 236 | * @see <a href="http://www.w3.org/TR/xquery-semantics/#sec_fn_insert_before">XQuery 1.0
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| 237 | * and XPath 2.0 Formal Semantics, 7.2.15 The fn:insert-before function</a>
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| 238 | */
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| 239 | virtual SequenceType::Ptr staticType() const;
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| 240 | };
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| 241 |
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| 242 | /**
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| 243 | * @short Implements the function <tt>fn:remove()</tt>.
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| 244 | *
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| 245 | * @ingroup Patternist_functions
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| 246 | * @author Frans Englich <[email protected]>
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| 247 | */
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| 248 | class RemoveFN : public FunctionCall
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| 249 | {
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| 250 | public:
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| 251 | virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
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| 252 | virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
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| 253 |
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| 254 | /**
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| 255 | * Implements the static enferences rules, "Since one item may be removed
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| 256 | * from the sequence, the resulting type is made optional:"
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| 257 | *
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| 258 | * <tt>statEnv |- (FN-URI,"remove")(Type, Type1) : prime(Type) * quantifier(Type)?</tt>
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| 259 | *
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| 260 | * However, because Patternist's type system is more fine grained than Formal Semantics,
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| 261 | * the sequence isn't made optional. Instead its minimum length is reduced with one.
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| 262 | *
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| 263 | * @see <a href="http://www.w3.org/TR/xquery-semantics/#sec_fn_remove">XQuery 1.0
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| 264 | * and XPath 2.0 Formal Semantics, 7.2.11 The fn:remove function</a>
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| 265 | */
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| 266 | virtual SequenceType::Ptr staticType() const;
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| 267 | };
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| 268 |
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| 269 | /**
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| 270 | * @short Implements the function <tt>fn:reverse()</tt>.
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| 271 | *
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| 272 | * @ingroup Patternist_functions
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| 273 | * @author Frans Englich <[email protected]>
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| 274 | */
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| 275 | class ReverseFN : public FunctionCall
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| 276 | {
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| 277 | public:
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| 278 |
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| 279 | virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
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| 280 | virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
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| 281 | const SequenceType::Ptr &reqType);
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| 282 |
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| 283 | /**
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| 284 | * Formally speaking, the type inference is:
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| 285 | *
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| 286 | @verbatim
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| 287 | statEnv |- (FN-URI,"reverse")(Type) : prime(Type) * quantifier(Type)
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| 288 | @endverbatim
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| 289 | *
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| 290 | * @see <a href="http://www.w3.org/TR/xquery-semantics/#sec_fn_reverse">XQuery 1.0
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| 291 | * and XPath 2.0 Formal Semantics, 7.2.12 The fn:reverse function</a>
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| 292 | * @returns the static type of the function's first argument.
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| 293 | */
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| 294 | virtual SequenceType::Ptr staticType() const;
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| 295 | };
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| 296 |
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| 297 | /**
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| 298 | * @short Implements the function <tt>fn:subsequence()</tt>.
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| 299 | *
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| 300 | * @ingroup Patternist_functions
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| 301 | * @author Frans Englich <[email protected]>
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| 302 | * @todo Type inference can be made stronger for this function
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| 303 | */
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| 304 | class SubsequenceFN : public FunctionCall
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| 305 | {
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| 306 | public:
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| 307 | SubsequenceFN();
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| 308 | virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
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| 309 | virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
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| 310 |
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| 311 | virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
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| 312 | const SequenceType::Ptr &reqType);
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| 313 |
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| 314 | /**
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| 315 | * This function implements rewrites the SubsequenceFN instance into an
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| 316 | * empty sequence if its third argument, the sequence length argument, is
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| 317 | * evaluated and is effectively equal or less than zero.
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| 318 | */
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| 319 | virtual Expression::Ptr compress(const StaticContext::Ptr &context);
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| 320 |
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| 321 | /**
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| 322 | * Partially implements the static type inference rules.
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| 323 | *
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| 324 | * @see <a href="http://www.w3.org/TR/xquery-semantics/#sec_fn_subsequence">XQuery 1.0
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| 325 | * and XPath 2.0 Formal Semantics, 7.2.13 The fn:subsequence function</a>
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| 326 | */
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| 327 | virtual SequenceType::Ptr staticType() const;
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| 328 |
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| 329 | private:
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| 330 | bool m_hasTypeChecked;
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| 331 | };
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| 332 | }
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| 333 |
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| 334 | QT_END_NAMESPACE
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| 335 |
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| 336 | QT_END_HEADER
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| 337 |
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| 338 | #endif
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