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** This file is part of the QtXmlPatterns module of the Qt Toolkit. | |
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** GNU Lesser General Public License Usage | |
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** GNU General Public License Usage | |
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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 "qsinglecontainer_p.h" | |
#include "qcastingplatform_p.h" | |
QT_BEGIN_HEADER | |
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 | |
QT_END_HEADER | |
#endif |