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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_EmptySequence_H
53 #define Patternist_EmptySequence_H
55 #include <private/qemptycontainer_p.h>
64 * @short Implements the value instance of empty sequence: <tt>()</tt>.
66 * @author Frans Englich <frans.englich@nokia.com>
67 * @ingroup Patternist_xdm
69 class EmptySequence : public EmptyContainer
73 * @short Creates an EmptySequence that is a replacement for @p
76 * @see EmptySequence()
78 static Expression::Ptr create(const Expression *const replacementFor,
79 const StaticContext::Ptr &context);
83 * @short Creates an instance of EmptySequence.
85 * @note In most cases create() should be used, since it takes care of
86 * adjusting source location annotations.
90 inline EmptySequence()
94 virtual QString stringValue() const;
97 * @returns always an empty iterator, an instance of EmptyIterator.
99 virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &) const;
102 * @returns always @c null.
104 virtual Item evaluateSingleton(const DynamicContext::Ptr &) const;
109 virtual void evaluateToSequenceReceiver(const DynamicContext::Ptr &) const;
112 * @returns always @c false.
114 virtual bool evaluateEBV(const DynamicContext::Ptr &context) const;
117 * @returns always CommonSequenceTypes::Empty
119 virtual ItemType::Ptr type() const;
122 * @returns always CommonSequenceTypes::Empty
124 virtual SequenceType::Ptr staticType() const;
126 virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const;
127 virtual ID id() const;
128 virtual Properties properties() const;