source: trunk/src/xmlpatterns/functions/qfunctionsignature_p.h@ 944

/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation ([email protected])
**
** This file is part of the QtXmlPatterns module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights.  These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you have questions regarding the use of this file, please contact
** Nokia at [email protected].
** $QT_END_LICENSE$
**
****************************************************************************/

//
//  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 <[email protected]>
     */
    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;

        /**