Qt 4.8
qletclause.cpp
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41 
42 #include "qboolean_p.h"
43 #include "qcommonsequencetypes_p.h"
44 #include "qdynamiccontextstore_p.h"
45 #include "qliteral_p.h"
46 
47 #include "qletclause_p.h"
48 
50 
51 using namespace QPatternist;
52 
54  const Expression::Ptr &operand2,
55  const VariableDeclaration::Ptr &decl) : PairContainer(operand1, operand2)
56  , m_varDecl(decl)
57 {
59 }
60 
62 {
64  return context;
65 }
66 
68 {
69  return m_operand2->evaluateSequence(bindVariable(context));
70 }
71 
73 {
74  return m_operand2->evaluateSingleton(bindVariable(context));
75 }
76 
77 bool LetClause::evaluateEBV(const DynamicContext::Ptr &context) const
78 {
79  return m_operand2->evaluateEBV(bindVariable(context));
80 }
81 
83 {
85 }
86 
88  const SequenceType::Ptr &reqType)
89 {
90  /* Consider the following query:
91  *
92  * <tt>let $d := <child type=""/>
93  * return $d//\*[let $i := @type
94  * return $d//\*[$i]]</tt>
95  *
96  * The node test <tt>@type</tt> is referenced from two different places,
97  * where each reference have a different focus. So, in the case of that the source
98  * uses the focus, we need to use a DynamicContextStore to ensure the variable
99  * is always evaluated with the correct focus, regardless of where it is referenced
100  * from.
101  *
102  * We miss out a lot of false positives. For instance, the case of where the focus
103  * is identical for everyone. One reason we cannot check this, is that Expression
104  * doesn't know about its parent.
105  */
106  m_varDecl->canSourceRewrite = !m_operand1->deepProperties().testFlag(RequiresFocus);
107 
108  if(m_varDecl->canSourceRewrite)
109  return m_operand2->typeCheck(context, reqType);
110  else
111  return PairContainer::typeCheck(context, reqType);
112 }
113 
115 {
117 }
118 
120 {
121  SequenceType::List result;
124  return result;
125 }
126 
128 {
129  return m_operand2->staticType();
130 }
131 
133 {
134  return visitor->visit(this);
135 }
136 
138 {
139  return IDLetClause;
140 }
141 
virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const
Definition: qletclause.cpp:72
virtual bool evaluateEBV(const DynamicContext::Ptr &context) const
Definition: qletclause.cpp:77
const VariableDeclaration::Ptr m_varDecl
Definition: qletclause_p.h:101
#define QT_END_NAMESPACE
This macro expands to.
Definition: qglobal.h:90
static const SequenceType::Ptr ZeroOrMoreItems
virtual Properties properties() const
Definition: qletclause.cpp:114
virtual bool evaluateEBV(const DynamicContext::Ptr &context) const
virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context, const SequenceType::Ptr &reqType)
Definition: qexpression.cpp:70
bool testFlag(Enum f) const
Returns true if the flag is set, otherwise false.
Definition: qglobal.h:2345
virtual void setExpressionVariable(const VariableSlotID slot, const QExplicitlySharedDataPointer< Expression > &newValue)=0
virtual void evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const
Definition: qletclause.cpp:82
#define Q_ASSERT(cond)
Definition: qglobal.h:1823
void append(const T &t)
Inserts value at the end of the list.
Definition: qlist.h:507
#define QT_BEGIN_NAMESPACE
This macro expands to.
Definition: qglobal.h:89
LetClause(const Expression::Ptr &operand1, const Expression::Ptr &operand2, const VariableDeclaration::Ptr &decl)
Definition: qletclause.cpp:53
The namespace for the internal API of QtXmlPatterns.
virtual ID id() const
Definition: qletclause.cpp:137
virtual SequenceType::List expectedOperandTypes() const
Definition: qletclause.cpp:119
DynamicContext::Ptr bindVariable(const DynamicContext::Ptr &context) const
Definition: qletclause.cpp:61
virtual SequenceType::Ptr staticType() const =0
Represents an item in the XPath 2.0 Data Model.
Definition: qitem_p.h:182
Properties deepProperties() const
Computes the union of properties for this Expression and all its descending children.
virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const
Definition: qletclause.cpp:67
The QFlags class provides a type-safe way of storing OR-combinations of enum values.
Definition: qglobal.h:2313
virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const
Definition: qletclause.cpp:132
virtual SequenceType::Ptr staticType() const
Definition: qletclause.cpp:127
virtual void evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const
virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context, const SequenceType::Ptr &reqType)
Definition: qletclause.cpp:87
virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const
The QList class is a template class that provides lists.
Definition: qdatastream.h:62
virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const
Base class for expressions that has exactly two operands.