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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_VariableDeclaration_H
51#define Patternist_VariableDeclaration_H
52
53#include <QSharedData>
54
55#include <private/qexpression_p.h>
56#include <private/qpatternistlocale_p.h>
57#include <private/qvariablereference_p.h>
58
59QT_BEGIN_NAMESPACE
60
61template<typename T> class QStack;
62
63namespace QPatternist
64{
65 /**
66 * @short Represents a declared variable. Only used at
67 * the compilation stage.
68 *
69 * @see FunctionArgument
70 * @author Frans Englich <frans.englich@nokia.com>
71 * @ingroup Patternist_expressions
72 */
73 class VariableDeclaration : public QSharedData
74 {
75 public:
76 typedef QExplicitlySharedDataPointer<VariableDeclaration> Ptr;
77 typedef QStack<VariableDeclaration::Ptr> Stack;
78 typedef QList<VariableDeclaration::Ptr> List;
79
80 /**
81 * @short The key is the variable name.
82 */
83 typedef QHash<QXmlName, VariableDeclaration::Ptr> Hash;
84
85 enum Type
86 {
87 RangeVariable,
88 ExpressionVariable,
89 FunctionArgument,
90 PositionalVariable,
91 TemplateParameter,
92
93 /**
94 * A global variable is always an external variable, but it is
95 * cached differently.
96 *
97 * @see DynamicContext::globalItemCacheCell()
98 */
99 GlobalVariable,
100
101 /**
102 * External variables doesn't use slots, that's a big difference
103 * compared to the other types.
104 */
105 ExternalVariable
106 };
107
108 /**
109 * Creates a VariableDeclaration.
110 *
111 * @p sourceExpr and @p seqType may be @c null.
112 */
113 VariableDeclaration(const QXmlName n,
114 const VariableSlotID varSlot,
115 const Type t,
116 const SequenceType::Ptr &seqType) : name(n)
117 , slot(varSlot)
118 , type(t)
119 , sequenceType(seqType)
120 , canSourceRewrite(true)
121 {
122 Q_ASSERT(!name.isNull());
123 Q_ASSERT(t == ExternalVariable || t == TemplateParameter || varSlot > -1);
124 }
125
126 inline bool isUsed() const
127 {
128 return !references.isEmpty();
129 }
130
131 inline const Expression::Ptr &expression() const
132 {
133 return m_expression;
134 }
135
136 inline void setExpression(const Expression::Ptr &expr)
137 {
138 m_expression = expr;
139 }
140
141 /**
142 * @short Returns how many times this variable is used.
143 */
144 inline bool usedByMany() const
145 {
146 return references.count() > 1;
147 }
148
149 /**
150 * @short Returns @c true if @p list contains @p lookup.
151 */
152 static bool contains(const VariableDeclaration::List &list,
153 const QXmlName &lookup);
154
155 const QXmlName name;
156 const VariableSlotID slot;
157 const Type type;
158
159 /**
160 * The declared type of the variable. What the value might be, depends
161 * on the context which VariableDeclaration is used in. Note that
162 * sequenceType is hence not in anyway obligated to the type of
163 * expression().
164 */
165 const SequenceType::Ptr sequenceType;
166 VariableReference::List references;
167
168 /**
169 * @short Whether a reference can rewrite itself to expression().
170 *
171 * The default value is @c true.
172 */
173 bool canSourceRewrite;
174
175 private:
176 Expression::Ptr m_expression;
177 Q_DISABLE_COPY(VariableDeclaration)
178 };
179
180 /**
181 * @short Formats @p var appropriately for display.
182 *
183 * @relates VariableDeclaration
184 */
185 static inline QString formatKeyword(const VariableDeclaration::Ptr &var,
186 const NamePool::Ptr &np)
187 {
188 Q_ASSERT(var);
189 Q_ASSERT(np);
190 return formatKeyword(keyword: np->displayName(qName: var->name));
191 }
192
193}
194
195QT_END_NAMESPACE
196
197#endif
198

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