/**************************************************************************** ** ** 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_NodeComparison_H #define Patternist_NodeComparison_H #include "qpaircontainer_p.h" QT_BEGIN_HEADER QT_BEGIN_NAMESPACE namespace QPatternist { /** * @short Implements the node comparison operators \>\>, \<\<, and @c is. * * @see XML Path Language * (XPath) 2.0, 3.5.3 QXmlNodeModelIndex Comparisons * @author Frans Englich * @ingroup Patternist_expressions */ class Q_AUTOTEST_EXPORT NodeComparison : public PairContainer { public: NodeComparison(const Expression::Ptr &operand1, const QXmlNodeModelIndex::DocumentOrder op, const Expression::Ptr &operand2); virtual Item evaluateSingleton(const DynamicContext::Ptr &) const; virtual bool evaluateEBV(const DynamicContext::Ptr &) const; virtual SequenceType::List expectedOperandTypes() const; virtual QXmlNodeModelIndex::DocumentOrder operatorID() const; /** * If any operator is the empty sequence, the NodeComparison rewrites * into that, since the empty sequence is always the result in that case. */ virtual Expression::Ptr compress(const StaticContext::Ptr &context); /** * @returns either CommonSequenceTypes::ZeroOrOneBoolean or * CommonSequenceTypes::ExactlyOneBoolean depending on the static * cardinality of its operands. */ virtual SequenceType::Ptr staticType() const; /** * Determines the string representation for a node comparison operator. * * @returns * - "<<" if @p op is Precedes * - ">>" if @p op is Follows * - "is" if @p op is Is */ static QString displayName(const QXmlNodeModelIndex::DocumentOrder op); virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const; private: enum Result { Empty, True, False }; inline Result evaluate(const DynamicContext::Ptr &context) const; const QXmlNodeModelIndex::DocumentOrder m_op; }; } QT_END_NAMESPACE QT_END_HEADER #endif