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46 // This file is not part of the Qt API. It exists purely as an
47 // implementation detail. This header file may change from version to
48 // version without notice, or even be removed.
52 #ifndef Patternist_Path_H
53 #define Patternist_Path_H
55 #include <private/qpaircontainer_p.h>
65 * @short Implements the path expression, containing two steps, such as in <tt>html/body</tt>.
67 * @see <a href="http://www.w3.org/TR/xquery/#id-path-expressions">XQuery 1.0: An
68 * XML Query Language, 3.2 Path Expressions</a>
69 * @author Frans Englich <frans.englich@nokia.com>
70 * @ingroup Patternist_expressions
72 class Path : public PairContainer
78 * This Path is a plain old path expression as found in XPath.
79 * Sorting is performed, and atomics are disallowed as left
85 * This Path emulates an @c xsl:for-each instruction. This means no
86 * sorting of result, and atomics are allowed as left operand.
91 * This Path performs the iteration in an @c xsl:apply-templates
92 * instruction. This means sorting, and atomics are disallowed
98 Path(const Expression::Ptr &operand1,
99 const Expression::Ptr &operand2,
100 const Kind kind = RegularPath);
102 virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
103 virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
104 virtual void evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const;
105 inline Item::Iterator::Ptr mapToSequence(const Item &item,
106 const DynamicContext::Ptr &context) const;
108 virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
109 const SequenceType::Ptr &reqType);
111 virtual SequenceType::List expectedOperandTypes() const;
114 * @returns the static type of the last step where the cardinality is multiplied with
115 * the cardinality of the first step's cardinality.
117 virtual SequenceType::Ptr staticType() const;
119 virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const;
121 virtual Properties properties() const;
123 virtual Expression::Ptr compress(const StaticContext::Ptr &context);
126 * @returns the item type of the last step's static type.
128 virtual ItemType::Ptr newFocusType() const;
130 virtual ID id() const;
132 inline void setLast();
134 inline Kind kind() const
140 typedef QExplicitlySharedDataPointer<const Path> ConstPtr;
143 * One might think this block exists for preventing multiple
144 * NodeSortExpressions to be created. However, that is not an issue,
145 * since NodeSortExpression optimizes this away anyway.
147 * The real reason is to avoid infinite recursion. When our typeCheck()
148 * forwards on the type check to the just created
149 * NodeSortExpression, it in turn calls typeCheck() on its child, which
150 * is this Path. Rince and repeat.
152 * We only create node sorts when we're a regular path expression, and
153 * not when standing in as a generic map expression. */
154 bool m_hasCreatedSorter;
157 * Whether this path is the step. For instance, in <tt>a/b/c</tt>, the
158 * last path has @c c as the right operand.
162 bool m_checkXPTY0018;