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    41 

    42 //

    43 //  W A R N I N G

    44 //  -------------

    45 //

    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.

    49 //

    50 // We mean it.

    51 

    52 #ifndef Patternist_FunctionSignature_H

    53 #define Patternist_FunctionSignature_H

    54 

    55 template<typename Key, typename Value> class QHash;

    56 template<typename T> class QList;

    57 

    58 #include <QSharedData>

    59 

    60 #include "qcalltargetdescription_p.h"

    61 #include "qexpression_p.h"

    62 #include "qfunctionargument_p.h"

    63 #include "qpatternistlocale_p.h"

    64 #include "qprimitives_p.h"

    65 

    66 QT_BEGIN_HEADER

    67 

    68 QT_BEGIN_NAMESPACE

    69 

    70 namespace QPatternist

    71 {

    72 

    73     /**

    74      * @short Represents the signature of an XPath function.

    75      *

    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.

    86      *

    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>

    92      */

    93     class Q_AUTOTEST_EXPORT FunctionSignature : public CallTargetDescription

    94     {

    95     public:

    96         enum

    97         {

    98             /**

    99              * Flags the function as allowing an unlimited amount of arguments.

   100              */

   101             UnlimitedArity = -1

   102         };

   103 

   104         typedef QExplicitlySharedDataPointer<FunctionSignature> Ptr;

   105         typedef QHash<QXmlName, FunctionSignature::Ptr> Hash;

   106         typedef QList<FunctionSignature::Ptr> List;

   107 

   108         /**

   109          * A number which tells the amount of arguments a function has.

   110          */

   111         typedef qint16 Arity;

   112 

   113         FunctionSignature(const QXmlName name,

   114                           const Arity minArgs,

   115                           const Arity maxArgs,

   116                           const SequenceType::Ptr &returnType,

   117                           const Expression::Properties chars = Expression::Properties(),

   118                           const Expression::ID id = Expression::IDIgnorableExpression);

   119 

   120         void setArguments(const FunctionArgument::List &args);

   121         FunctionArgument::List arguments() const;

   122 

   123         /**

   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

   126          * and type @p type.

   127          */

   128         void appendArgument(const QXmlName::LocalNameCode name,

   129                             const SequenceType::Ptr &type);

   130 

   131         /**

   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.

   135          */

   136         bool isArityValid(const xsInteger arity) const;

   137 

   138         Arity minimumArguments() const;

   139         Arity maximumArguments() const;

   140 

   141         /**

   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>.

   144          */

   145         SequenceType::Ptr returnType() const;

   146 

   147         /**

   148          * The properties that the corresponding FunctionCall instance should return in

   149          * Expression::properties().

   150          */

   151         Expression::Properties properties() const;

   152 

   153         /**

   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().

   158          *

   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.

   162          *

   163          * @returns @c true if this FunctionSignature is equal to @p other, otherwise @c false

   164          */

   165         bool operator==(const FunctionSignature &other) const;

   166 

   167         /**

   168          * Builds a string representation for this function signature. The syntax

   169          * used is the one used in the XQuery. It looks like this:

   170          *

   171          * <tt>prefix:function-name($parameter-name as parameter-type, ...) as return-type</tt>

   172          *

   173          * The prefix used for the name is conventional. For example, for constructor functions

   174          * is @c xs used.

   175          *

   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>

   178          */

   179         QString displayName(const NamePool::Ptr &np) const;

   180 

   181         /**

   182          * The ID that the corresponding FunctionCall instance should return in

   183          * Expression::id().

   184          */

   185         Expression::ID id() const;

   186 

   187     private:

   188         Q_DISABLE_COPY(FunctionSignature)

   189 

   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;

   196     };

   197 

   198     /**

   199      * @short Formats FunctionSignature.

   200      */

   201     static inline QString formatFunction(const NamePool::Ptr &np, const FunctionSignature::Ptr &func)

   202     {

   203         return QLatin1String("<span class='XQuery-function'>")  +

   204                escape(func->displayName(np))                    +

   205                QLatin1String("</span>");

   206     }

   207 }

   208 

   209 QT_END_NAMESPACE

   210 

   211 QT_END_HEADER

   212 

   213 #endif