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/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtXmlPatterns module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the either Technology Preview License Agreement or the
** Beta Release License Agreement.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain
** additional rights. These rights are described in the Nokia Qt LGPL
** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
** package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at http://qt.nokia.com/contact.
** $QT_END_LICENSE$
**
****************************************************************************/
//
// 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 <fenglich@trolltech.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
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