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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_AggregateFNs_H
51#define Patternist_AggregateFNs_H
52
53#include <private/qaggregator_p.h>
54#include <private/qatomiccomparator_p.h>
55#include <private/qatomicmathematician_p.h>
56#include <private/qcomparisonplatform_p.h>
57
58/**
59 * @file
60 * @short Contains classes implementing the functions found in
61 * <a href="http://www.w3.org/TR/xpath-functions/#aggregate-functions">XQuery 1.0 and
62 * XPath 2.0 Functions and Operators, 15.4 Aggregate Functions</a>.
63 *
64 * @todo document that some functions have both eval funcs implented.
65 *
66 * @ingroup Patternist_functions
67 */
68
69QT_BEGIN_NAMESPACE
70
71namespace QPatternist
72{
73 /**
74 * @short Implements the function <tt>fn:count()</tt>.
75 *
76 * @ingroup Patternist_functions
77 * @author Frans Englich <frans.englich@nokia.com>
78 */
79 class CountFN : public FunctionCall
80 {
81 public:
82 virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
83
84 /**
85 * If @p reqType is CommonSequenceTypes::EBV, this function call is rewritten
86 * into a call to <tt>fn:exists()</tt>. Hence, <tt>if(count(X)) then ...</tt> is
87 * rewritten into <tt>if(exists(X)) then ...</tt>.
88 */
89 virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
90 const SequenceType::Ptr &reqType);
91 /**
92 * If CountFN's operand has a Cardinality that is exact, as per Cardinality::isExact(),
93 * it is rewritten to the Cardinality's count.
94 */
95 virtual Expression::Ptr compress(const StaticContext::Ptr &context);
96 };
97
98 /**
99 * @short Base class for the implementations of the <tt>fn:avg()</tt> and <tt>fn:sum()</tt> function.
100 *
101 * @ingroup Patternist_functions
102 * @author Frans Englich <frans.englich@nokia.com>
103 */
104 class AddingAggregate : public FunctionCall
105 {
106 public:
107 virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
108 const SequenceType::Ptr &reqType);
109 protected:
110 AtomicMathematician::Ptr m_mather;
111 };
112
113 /**
114 * @short Implements the function <tt>fn:avg()</tt>.
115 *
116 * @ingroup Patternist_functions
117 * @author Frans Englich <frans.englich@nokia.com>
118 */
119 class AvgFN : public AddingAggregate
120 {
121 public:
122 virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
123 virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
124 const SequenceType::Ptr &reqType);
125
126 virtual SequenceType::Ptr staticType() const;
127 private:
128 AtomicMathematician::Ptr m_adder;
129 AtomicMathematician::Ptr m_divider;
130 };
131
132 /**
133 * @short Implements the function <tt>fn:sum()</tt>.
134 *
135 * @ingroup Patternist_functions
136 * @author Frans Englich <frans.englich@nokia.com>
137 */
138 class SumFN : public AddingAggregate
139 {
140 public:
141 virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
142 virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
143 const SequenceType::Ptr &reqType);
144 virtual SequenceType::Ptr staticType() const;
145 };
146}
147
148QT_END_NAMESPACE
149
150#endif
151

source code of qtxmlpatterns/src/xmlpatterns/functions/qaggregatefns_p.h