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| |
| // |
| // W A R N I N G |
| // ------------- |
| // |
| // This file is not part of the Qt API. It exists purely as an |
| // implementation detail. This header file may change from version to |
| // version without notice, or even be removed. |
| // |
| // We mean it. |
| |
| #ifndef Patternist_CastAs_H |
| #define Patternist_CastAs_H |
| |
| #include <private/qsinglecontainer_p.h> |
| #include <private/qcastingplatform_p.h> |
| |
| QT_BEGIN_NAMESPACE |
| |
| namespace QPatternist |
| { |
| /** |
| * @short Implements XPath 2.0's <tt>cast as</tt> expression. |
| * |
| * Implements the casting expression, such as <tt>'3' cast as xs:integer</tt>. This class also |
| * implements constructor functions, which are created in the ConstructorFunctionsFactory. |
| * |
| * CastAs uses CastingPlatform for carrying out the actual casting. |
| * |
| * @see <a href="http://www.w3.org/TR/xpath-functions/#casting">XQuery 1.0 |
| * and XPath 2.0 Functions and Operators, 7 Casting</a> |
| * @see <a href="http://www.w3.org/TR/xpath20/#id-cast">XML Path Language |
| * (XPath) 2.0, 3.10.2 Cast</a> |
| * @author Frans Englich <frans.englich@nokia.com> |
| * @ingroup Patternist_expressions |
| */ |
| class CastAs : public SingleContainer, |
| public CastingPlatform<CastAs, true /* issueError */> |
| { |
| public: |
| |
| /** |
| * @todo Wrong/old documentation |
| * |
| * Creates a cast expression for the type @p name via the schema type |
| * factory @p factory. This function is used by parser when creating |
| * 'cast to' expressions, and the ConstructorFunctionsFactory, when creating |
| * constructor functions. |
| * |
| * @param targetType the type which the CastAs should cast to |
| * @param source the operand to evaluate and then cast from |
| */ |
| CastAs(const Expression::Ptr &source, |
| const SequenceType::Ptr &targetType); |
| |
| virtual Item evaluateSingleton(const DynamicContext::Ptr &) const; |
| |
| virtual SequenceType::List expectedOperandTypes() const; |
| |
| /** |
| * @returns a SequenceType where the ItemType is this CastAs's |
| * target type, as per targetType(), and the Cardinality is inferred from the |
| * source operand to reflect whether this CastAs always will evaluate to |
| * exactly-one or zero-or-one values. |
| */ |
| virtual SequenceType::Ptr staticType() const; |
| |
| /** |
| * Overridden in order to check that casting to an abstract type |
| * is not attempted. |
| */ |
| virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context, |
| const SequenceType::Ptr &reqType); |
| |
| /** |
| * If the target type is the same as the source type, it is rewritten |
| * to the operand. |
| */ |
| virtual Expression::Ptr compress(const StaticContext::Ptr &context); |
| virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const; |
| |
| inline ItemType::Ptr targetType() const |
| { |
| return m_targetType->itemType(); |
| } |
| |
| inline SequenceType::Ptr targetSequenceType() const |
| { |
| return m_targetType; |
| } |
| |
| private: |
| /** |
| * Performs casting to @c xs:QName. This case is special, and is always done at compile time. |
| */ |
| Expression::Ptr castToQName(const StaticContext::Ptr &context) const; |
| |
| const SequenceType::Ptr m_targetType; |
| }; |
| } |
| |
| QT_END_NAMESPACE |
| |
| #endif |