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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_TreatAs_H
53 #define Patternist_TreatAs_H
55 #include <private/qsinglecontainer_p.h>
64 * @short Implements XPath 2.0's <tt>treat as</tt> expression.
66 * TreatAs is always a compile-time class only, and is always deallocated
67 * by re-writing to CardinalityVerifier or ItemVerifier or both, by calling
68 * TypeChecker::applyFunctionConversion().
71 * One approach could be to skip instantiating TreatAs and simply let the
72 * return value of TypeChecker::applyFunctionConversion() be inserted into
73 * the AST, but that wouldn't handle type checking the context item
74 * properly, which depends on that the StaticContext have been set by the
77 * @see <a href="http://www.w3.org/TR/xpath20/#id-treat">XML Path Language
78 * (XPath) 2.0, 3.10.5 Treat</a>
79 * @author Frans Englich <frans.englich@nokia.com>
80 * @ingroup Patternist_expressions
82 class TreatAs : public SingleContainer
86 * Creats a TreatAs where it is checked that the expression @p operand conforms
87 * to the type @p reqType.
89 TreatAs(const Expression::Ptr &operand,
90 const SequenceType::Ptr &reqType);
93 * This function rewrites always. First the type that this TreatAs expression tests for
94 * is verified. Then, the type the <tt>treat as</tt> expression itself must match, @p reqType,
97 virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
98 const SequenceType::Ptr &reqType);
101 * @returns always the SequenceType passed in the constructor to this class. That is, the
102 * SequenceType that the operand must conform to.
104 virtual SequenceType::Ptr staticType() const;
107 * @returns a list containing one CommonSequenceTypes::ZeroOrMoreItems
109 virtual SequenceType::List expectedOperandTypes() const;
111 virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const;
114 const SequenceType::Ptr m_reqType;