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39
40//
41// W A R N I N G
42// -------------
43//
44// This file is not part of the Qt API. It exists purely as an
45// implementation detail. This header file may change from version to
46// version without notice, or even be removed.
47//
48// We mean it.
49
50#ifndef Patternist_LetClause_H
51#define Patternist_LetClause_H
52
53#include <private/qpaircontainer_p.h>
54#include <private/qvariabledeclaration_p.h>
55
56QT_BEGIN_NAMESPACE
57
58namespace QPatternist
59{
60
61 /**
62 * @short Represents a <tt>let</tt>-clause, but is only used at compile
63 * time.
64 *
65 * LetClause is inserted into the AST tree for the single purpose of
66 * ensuring that the focus is correct for the binding expression. Once
67 * that is done, LetClause sometimes rewrites itself to its
68 * <tt>return</tt> expression, and the ExpressionVariableReference will
69 * handle the evaluation of the variable.
70 *
71 * @author Frans Englich <frans.englich@nokia.com>
72 * @ingroup Patternist_expressions
73 */
74 class LetClause : public PairContainer
75 {
76 public:
77 LetClause(const Expression::Ptr &operand1,
78 const Expression::Ptr &operand2,
79 const VariableDeclaration::Ptr &decl);
80
81 virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
82 virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
83 virtual bool evaluateEBV(const DynamicContext::Ptr &context) const;
84 virtual void evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const;
85
86 virtual SequenceType::List expectedOperandTypes() const;
87 virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
88 const SequenceType::Ptr &reqType);
89 virtual SequenceType::Ptr staticType() const;
90 virtual Properties properties() const;
91 virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const;
92 virtual ID id() const;
93
94 private:
95 inline DynamicContext::Ptr bindVariable(const DynamicContext::Ptr &context) const;
96
97 const VariableDeclaration::Ptr m_varDecl;
98 };
99}
100
101QT_END_NAMESPACE
102
103#endif
104

source code of qtxmlpatterns/src/xmlpatterns/expr/qletclause_p.h