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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_CastAs_H
53 #define Patternist_CastAs_H
55 #include "qsinglecontainer_p.h"
56 #include "qcastingplatform_p.h"
65 * @short Implements XPath 2.0's <tt>cast as</tt> expression.
67 * Implements the casting expression, such as <tt>'3' cast as xs:integer</tt>. This class also
68 * implements constructor functions, which are created in the ConstructorFunctionsFactory.
70 * CastAs uses CastingPlatform for carrying out the actual casting.
72 * @see <a href="http://www.w3.org/TR/xpath-functions/#casting">XQuery 1.0
73 * and XPath 2.0 Functions and Operators, 7 Casting</a>
74 * @see <a href="http://www.w3.org/TR/xpath20/#id-cast">XML Path Language
75 * (XPath) 2.0, 3.10.2 Cast</a>
76 * @author Frans Englich <frans.englich@nokia.com>
77 * @ingroup Patternist_expressions
79 class CastAs : public SingleContainer,
80 public CastingPlatform<CastAs, true /* issueError */>
85 * @todo Wrong/old documentation
87 * Creates a cast expression for the type @p name via the schema type
88 * factory @p factory. This function is used by parser when creating
89 * 'cast to' expressions, and the ConstructorFunctionsFactory, when creating
90 * constructor functions.
92 * @param targetType the type which the CastAs should cast to
93 * @param source the operand to evaluate and then cast from
95 CastAs(const Expression::Ptr &source,
96 const SequenceType::Ptr &targetType);
98 virtual Item evaluateSingleton(const DynamicContext::Ptr &) const;
100 virtual SequenceType::List expectedOperandTypes() const;
103 * @returns a SequenceType where the ItemType is this CastAs's
104 * target type, as per targetType(), and the Cardinality is inferred from the
105 * source operand to reflect whether this CastAs always will evaluate to
106 * exactly-one or zero-or-one values.
108 virtual SequenceType::Ptr staticType() const;
111 * Overridden in order to check that casting to an abstract type
114 virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
115 const SequenceType::Ptr &reqType);
118 * If the target type is the same as the source type, it is rewritten
121 virtual Expression::Ptr compress(const StaticContext::Ptr &context);
122 virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const;
124 inline ItemType::Ptr targetType() const
126 return m_targetType->itemType();
129 inline SequenceType::Ptr targetSequenceType() const
136 * Performs casting to @c xs:QName. This case is special, and is always done at compile time.
138 Expression::Ptr castToQName(const StaticContext::Ptr &context) const;
140 const SequenceType::Ptr m_targetType;