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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_ReturnOrderBy_H
51#define Patternist_ReturnOrderBy_H
52
53#include <private/qorderby_p.h>
54#include <private/qunlimitedcontainer_p.h>
55
56QT_BEGIN_NAMESPACE
57
58namespace QPatternist
59{
60 /**
61 * @short Together with OrderBy, it implements XQuery 1.0's <tt>order by</tt> expression.
62 *
63 * ReturnOrderBy evaluates the sort keys and values, and hands it over to
64 * OrderBy, which is an AST ancestor, using SortTuples.
65 *
66 * @author Frans Englich <frans.englich@nokia.com>
67 * @ingroup Patternist_expressions
68 */
69 class ReturnOrderBy : public UnlimitedContainer
70 {
71 public:
72 /**
73 * In @p operands the first item is the return expression, and the
74 * rest, which is at least one, are the sort keys.
75 */
76 ReturnOrderBy(const OrderBy::Stability stability,
77 const OrderBy::OrderSpec::Vector &oSpecs,
78 const Expression::List &operands);
79
80 virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
81 virtual bool evaluateEBV(const DynamicContext::Ptr &context) const;
82 virtual SequenceType::Ptr staticType() const;
83 virtual SequenceType::List expectedOperandTypes() const;
84 virtual Expression::Ptr compress(const StaticContext::Ptr &context);
85 virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const;
86 virtual ID id() const;
87
88 inline OrderBy::OrderSpec::Vector orderSpecs() const
89 {
90 return m_orderSpecs;
91 }
92
93 inline OrderBy::Stability stability() const
94 {
95 return m_stability;
96 }
97
98 /**
99 * In the case of that we don't have a for-expression beloning us, but
100 * only a let clause, this ReturnOrderBy breaks if it stays in the AST.
101 * So, by default we assume that we should write ourselves away, unless
102 * this function is called. The associated ForClause will call it
103 * during typeCheck(), if it exists.
104 */
105 inline void setStay(const bool a)
106 {
107 m_flyAway = !a;
108 }
109
110 virtual Properties properties() const;
111 private:
112 /**
113 * This variable is unfortunately only used at compile time. However,
114 * it's tricky to get rid of it due to how QueryTransformParser would
115 * have to be adapted.
116 */
117 const OrderBy::Stability m_stability;
118
119 OrderBy::OrderSpec::Vector m_orderSpecs;
120
121 /**
122 * @see stay()
123 */
124 bool m_flyAway;
125 };
126}
127
128QT_END_NAMESPACE
129
130#endif
131

source code of qtxmlpatterns/src/xmlpatterns/expr/qreturnorderby_p.h