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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 Technology Preview License Agreement accompanying
** this package.
**
** 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 1.1, included in the file LGPL_EXCEPTION.txt in this
** package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
//
// 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_LetClause_H
#define Patternist_LetClause_H
#include "qpaircontainer_p.h"
#include "qvariabledeclaration_p.h"
QT_BEGIN_HEADER
QT_BEGIN_NAMESPACE
namespace QPatternist
{
/**
* @short Represents a <tt>let</tt>-clause, but is only used at compile
* time.
*
* LetClause is inserted into the AST tree for the single purpose of
* ensuring that the focus is correct for the binding expression. Once
* that is done, LetClause sometimes rewrites itself to its
* <tt>return</tt> expression, and the ExpressionVariableReference will
* handle the evaluation of the variable.
*
* @author Frans Englich <frans.englich@nokia.com>
* @ingroup Patternist_expressions
*/
class LetClause : public PairContainer
{
public:
LetClause(const Expression::Ptr &operand1,
const Expression::Ptr &operand2,
const VariableDeclaration::Ptr &decl);
virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
virtual bool evaluateEBV(const DynamicContext::Ptr &context) const;
virtual void evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const;
virtual SequenceType::List expectedOperandTypes() const;
virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
const SequenceType::Ptr &reqType);
virtual SequenceType::Ptr staticType() const;
virtual Properties properties() const;
virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const;
virtual ID id() const;
private:
inline DynamicContext::Ptr bindVariable(const DynamicContext::Ptr &context) const;
const VariableDeclaration::Ptr m_varDecl;
};
}
QT_END_NAMESPACE
QT_END_HEADER
#endif
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