--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/xmlpatterns/expr/qletclause.cpp	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,142 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** 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.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qboolean_p.h"
+#include "qcommonsequencetypes_p.h"
+#include "qdynamiccontextstore_p.h"
+#include "qliteral_p.h"
+
+#include "qletclause_p.h"
+
+QT_BEGIN_NAMESPACE
+
+using namespace QPatternist;
+
+LetClause::LetClause(const Expression::Ptr &operand1,
+                     const Expression::Ptr &operand2,
+                     const VariableDeclaration::Ptr &decl) : PairContainer(operand1, operand2)
+                                                           , m_varDecl(decl)
+{
+    Q_ASSERT(m_varDecl);
+}
+
+DynamicContext::Ptr LetClause::bindVariable(const DynamicContext::Ptr &context) const
+{
+    context->setExpressionVariable(m_varDecl->slot, Expression::Ptr(new DynamicContextStore(m_operand1, context)));
+    return context;
+}
+
+Item::Iterator::Ptr LetClause::evaluateSequence(const DynamicContext::Ptr &context) const
+{
+    return m_operand2->evaluateSequence(bindVariable(context));
+}
+
+Item LetClause::evaluateSingleton(const DynamicContext::Ptr &context) const
+{
+    return m_operand2->evaluateSingleton(bindVariable(context));
+}
+
+bool LetClause::evaluateEBV(const DynamicContext::Ptr &context) const
+{
+    return m_operand2->evaluateEBV(bindVariable(context));
+}
+
+void LetClause::evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const
+{
+    m_operand2->evaluateToSequenceReceiver(bindVariable(context));
+}
+
+Expression::Ptr LetClause::typeCheck(const StaticContext::Ptr &context,
+                                     const SequenceType::Ptr &reqType)
+{
+    /* Consider the following query:
+     *
+     * <tt>let $d := \<child type=""/>
+     * return $d//\*[let $i := @type
+     *              return $d//\*[$i]]</tt>
+     *
+     * The node test <tt>@type</tt> is referenced from two different places,
+     * where each reference have a different focus. So, in the case of that the source
+     * uses the focus, we need to use a DynamicContextStore to ensure the variable
+     * is always evaluated with the correct focus, regardless of where it is referenced
+     * from.
+     *
+     * We miss out a lot of false positives. For instance, the case of where the focus
+     * is identical for everyone. One reason we cannot check this, is that Expression
+     * doesn't know about its parent.
+     */
+    m_varDecl->canSourceRewrite = !m_operand1->deepProperties().testFlag(RequiresFocus);
+
+    if(m_varDecl->canSourceRewrite)
+        return m_operand2->typeCheck(context, reqType);
+    else
+        return PairContainer::typeCheck(context, reqType);
+}
+
+Expression::Properties LetClause::properties() const
+{
+    return m_varDecl->expression()->properties() & (Expression::RequiresFocus | Expression::IsEvaluated | Expression::DisableElimination);
+}
+
+SequenceType::List LetClause::expectedOperandTypes() const
+{
+    SequenceType::List result;
+    result.append(CommonSequenceTypes::ZeroOrMoreItems);
+    result.append(CommonSequenceTypes::ZeroOrMoreItems);
+    return result;
+}
+
+SequenceType::Ptr LetClause::staticType() const
+{
+    return m_operand2->staticType();
+}
+
+ExpressionVisitorResult::Ptr LetClause::accept(const ExpressionVisitor::Ptr &visitor) const
+{
+    return visitor->visit(this);
+}
+
+Expression::ID LetClause::id() const
+{
+    return IDLetClause;
+}
+
+QT_END_NAMESPACE