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46 // This file is not part of the Qt API. It exists purely as an
47 // implementation detail. This header file may change from version to
48 // version without notice, or even be removed.
52 #ifndef Patternist_FunctionSignature_H
53 #define Patternist_FunctionSignature_H
55 #include <QSharedData>
57 #include <private/qcalltargetdescription_p.h>
58 #include <private/qexpression_p.h>
59 #include <private/qfunctionargument_p.h>
60 #include <private/qpatternistlocale_p.h>
61 #include <private/qprimitives_p.h>
67 template<typename Key, typename Value> class QHash;
68 template<typename T> class QList;
74 * @short Represents the signature of an XPath function.
76 * FunctionSignature represents and allows inspection of a function signature,
77 * such as <tt>fn:string-join($arg1 as xs:string*, $arg2 as xs:string) as xs:string</tt>.
78 * No XPath related languages allows polymorphism on the type of the arguments, only the
79 * amount(arity) of the arguments. For example, <tt>fn:string() as xs:string</tt> and
80 * <tt>fn:string($arg as item()?) as xs:string</tt> can happily co-exist, but
81 * <tt>fn:string($arg as item()?) as xs:string</tt> and
82 * <tt>fn:string($arg as xs:anyAtomicType?) as xs:string</tt> would be an error. This
83 * fact is reflected by FunctionSignature that if minimumArguments() and maximumArguments()
84 * are not equal, it means that this FunctionSignature represents several
85 * function signatures.
87 * @ingroup Patternist_functions
88 * @see <a href="http://www.w3.org/TR/xpath-functions/#func-signatures">XQuery 1.0 and
89 * XPath 2.0 Functions and Operators, 1.4 Function Signatures and Descriptions</a>
90 * @see <a href="http://en.wikipedia.org/wiki/Arity">Wikipedia, the free encyclopedia, Arity</a>
91 * @author Frans Englich <frans.englich@nokia.com>
93 class Q_AUTOTEST_EXPORT FunctionSignature : public CallTargetDescription
99 * Flags the function as allowing an unlimited amount of arguments.
104 typedef QExplicitlySharedDataPointer<FunctionSignature> Ptr;
105 typedef QHash<QXmlName, FunctionSignature::Ptr> Hash;
106 typedef QList<FunctionSignature::Ptr> List;
109 * A number which tells the amount of arguments a function has.
111 typedef qint16 Arity;
113 FunctionSignature(const QXmlName name,
116 const SequenceType::Ptr &returnType,
117 const Expression::Properties chars = Expression::Properties(),
118 const Expression::ID id = Expression::IDIgnorableExpression);
120 void setArguments(const FunctionArgument::List &args);
121 FunctionArgument::List arguments() const;
124 * This is a convenience function. Calling this once, is equal to
125 * calling setArguments() with a list containing a FunctionsArgument with name @p name
128 void appendArgument(const QXmlName::LocalNameCode name,
129 const SequenceType::Ptr &type);
132 * Checks whether @p arity is within the range of allowed count of arguments. For example,
133 * when the minimum arguments is 1 and maximum arguments 2, @c false will be returned for
134 * passing 0 while @c true will be returned when 2 is passed.
136 bool isArityValid(const xsInteger arity) const;
138 Arity minimumArguments() const;
139 Arity maximumArguments() const;
142 * The return type of this function signature. For example, if the represented function
143 * signature is <tt>fn:string() as xs:string</tt>, the return type is <tt>xs:string</tt>.
145 SequenceType::Ptr returnType() const;
148 * The properties that the corresponding FunctionCall instance should return in
149 * Expression::properties().
151 Expression::Properties properties() const;
154 * Determines whether this FunctionSignature is equal to @p other, taking
155 * into account XPath's function polymorphism. @p other is equal to this
156 * FunctionSignature if their name() instances are equal, and that the maximumArguments()
157 * and minimumArguments() arguments of @p other are allowed, as per isArityValid().
159 * In other words, this equalness operator can return @c true for different
160 * signatures, but it do make sense since a FunctionSignature can represent
161 * multiple signatures.
163 * @returns @c true if this FunctionSignature is equal to @p other, otherwise @c false
165 bool operator==(const FunctionSignature &other) const;
168 * Builds a string representation for this function signature. The syntax
169 * used is the one used in the XQuery. It looks like this:
171 * <tt>prefix:function-name($parameter-name as parameter-type, ...) as return-type</tt>
173 * The prefix used for the name is conventional. For example, for constructor functions
176 * @see <a href="http://www.w3.org/TR/xpath-functions/#func-signatures">XQuery 1.0 and
177 * XPath 2.0 Functions and Operators, 1.4 Function Signatures and Descriptions</a>
179 QString displayName(const NamePool::Ptr &np) const;
182 * The ID that the corresponding FunctionCall instance should return in
185 Expression::ID id() const;
188 Q_DISABLE_COPY(FunctionSignature)
190 const Arity m_minArgs;
191 const Arity m_maxArgs;
192 const SequenceType::Ptr m_returnType;
193 FunctionArgument::List m_arguments;
194 const Expression::Properties m_props;
195 const Expression::ID m_id;
199 * @short Formats FunctionSignature.
201 static inline QString formatFunction(const NamePool::Ptr &np, const FunctionSignature::Ptr &func)
203 return QLatin1String("<span class='XQuery-function'>") +
204 escape(func->displayName(np)) +
205 QLatin1String("</span>");