/****************************************************************************
**
** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtXmlPatterns module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
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** use the contact form at http://qt.digia.com/contact-us.
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** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
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** following information to ensure the GNU Lesser General Public License
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** In addition, as a special exception, Digia gives you certain additional
** rights. These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
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** $QT_END_LICENSE$
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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_ErrorFN_H
#define Patternist_ErrorFN_H

#include <private/qfunctioncall_p.h>

QT_BEGIN_NAMESPACE

namespace QPatternist
{

    /**
     * @short Implements the function <tt>fn:error()</tt>.
     *
     * <tt>fn:error()</tt> is a bit special in that its first argument varies between
     * the different signatures. This is implemented by changing the function
     * signature if the amount of arguments is one.
     *
     * <tt>fn:error()</tt> has as return type the peculiar "none" type, which is handled by NoneType.
     *
     * @ingroup Patternist_functions
     * @see CommonSequenceTypes::none
     * @see <a href="http://www.w3.org/TR/xpath-functions/#func-error">XQuery 1.0 and
     * XPath 2.0 Functions and Operators, 3 The Error Function</a>
     * @author Frans Englich <frans.englich@nokia.com>
     */
    class ErrorFN : public FunctionCall
    {
    public:
        virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
        virtual FunctionSignature::Ptr signature() const;
    };
}

QT_END_NAMESPACE

#endif
