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//

//  W A R N I N G

//  -------------

//

// This file is not part of the Qt API.  It exists purely as an

// implementation detail.  This header file may change from version to

// version without notice, or even be removed.

//

// We mean it.

#ifndef Patternist_FunctionSignature_H

#define Patternist_FunctionSignature_H

template<typename Key, typename Value> class QHash;

template<typename T> class QList;

#include <QSharedData>

#include "qcalltargetdescription_p.h"

#include "qexpression_p.h"

#include "qfunctionargument_p.h"

#include "qpatternistlocale_p.h"

#include "qprimitives_p.h"

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist

{

    /**

     * @short Represents the signature of an XPath function.

     *

     * FunctionSignature represents and allows inspection of a function signature,

     * such as <tt>fn:string-join($arg1 as xs:string*, $arg2 as xs:string) as xs:string</tt>.

     * No XPath related languages allows polymorphism on the type of the arguments, only the

     * amount(arity) of the arguments. For example, <tt>fn:string() as xs:string</tt> and

     * <tt>fn:string($arg as item()?) as xs:string</tt> can happily co-exist, but

     * <tt>fn:string($arg as item()?) as xs:string</tt> and

     * <tt>fn:string($arg as xs:anyAtomicType?) as xs:string</tt> would be an error. This

     * fact is reflected by FunctionSignature that if minimumArguments() and maximumArguments()

     * are not equal, it means that this FunctionSignature represents several

     * function signatures.

     *

     * @ingroup Patternist_functions

     * @see <a href="http://www.w3.org/TR/xpath-functions/#func-signatures">XQuery 1.0 and

     * XPath 2.0 Functions and Operators, 1.4 Function Signatures and Descriptions</a>

     * @see <a href="http://en.wikipedia.org/wiki/Arity">Wikipedia, the free encyclopedia, Arity</a>

     * @author Frans Englich <frans.englich@nokia.com>

     */

    class Q_AUTOTEST_EXPORT FunctionSignature : public CallTargetDescription

    {

    public:

        enum

        {

            /**

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

             */

            UnlimitedArity = -1

        };

        typedef QExplicitlySharedDataPointer<FunctionSignature> Ptr;

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

        typedef QList<FunctionSignature::Ptr> List;

        /**

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

         */

        typedef qint16 Arity;

        FunctionSignature(const QXmlName name,

                          const Arity minArgs,

                          const Arity maxArgs,

                          const SequenceType::Ptr &returnType,

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

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

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

        FunctionArgument::List arguments() const;

        /**

         * This is a convenience function. Calling this once, is equal to

         * calling setArguments() with a list containing a FunctionsArgument with name @p name

         * and type @p type.

         */

        void appendArgument(const QXmlName::LocalNameCode name,

                            const SequenceType::Ptr &type);

        /**

         * Checks whether @p arity is within the range of allowed count of arguments. For example,

         * when the minimum arguments is 1 and maximum arguments 2, @c false will be returned for

         * passing 0 while @c true will be returned when 2 is passed.

         */

        bool isArityValid(const xsInteger arity) const;

        Arity minimumArguments() const;

        Arity maximumArguments() const;

        /**

         * The return type of this function signature. For example, if the represented function

         * signature is <tt>fn:string() as xs:string</tt>, the return type is <tt>xs:string</tt>.

         */

        SequenceType::Ptr returnType() const;

        /**

         * The properties that the corresponding FunctionCall instance should return in

         * Expression::properties().

         */

        Expression::Properties properties() const;

        /**

         * Determines whether this FunctionSignature is equal to @p other, taking

         * into account XPath's function polymorphism. @p other is equal to this

         * FunctionSignature if their name() instances are equal, and that the maximumArguments()

         * and minimumArguments() arguments of @p other are allowed, as per isArityValid().

         *

         * In other words, this equalness operator can return @c true for different

         * signatures, but it do make sense since a FunctionSignature can represent

         * multiple signatures.

         *

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

         */

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

        /**

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

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

         *

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

         *

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

         * is @c xs used.

         *

         * @see <a href="http://www.w3.org/TR/xpath-functions/#func-signatures">XQuery 1.0 and

         * XPath 2.0 Functions and Operators, 1.4 Function Signatures and Descriptions</a>

         */

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

        /**

         * The ID that the corresponding FunctionCall instance should return in

         * Expression::id().

         */

        Expression::ID id() const;

    private:

        Q_DISABLE_COPY(FunctionSignature)

        const Arity                     m_minArgs;

        const Arity                     m_maxArgs;

        const SequenceType::Ptr         m_returnType;

        FunctionArgument::List          m_arguments;

        const Expression::Properties    m_props;

        const Expression::ID            m_id;

    };

    /**

     * @short Formats FunctionSignature.

     */

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

    {

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

               escape(func->displayName(np))                    +

               QLatin1String("</span>");

    }

}

QT_END_NAMESPACE

QT_END_HEADER

#endif