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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_AggregateFNs_H

#define Patternist_AggregateFNs_H

#include "qaggregator_p.h"

#include "qatomiccomparator_p.h"

#include "qatomicmathematician_p.h"

#include "qcomparisonplatform_p.h"

/**

 * @file

 * @short Contains classes implementing the functions found in

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

 * XPath 2.0 Functions and Operators, 15.4 Aggregate Functions</a>.

 *

 * @todo document that some functions have both eval funcs implented.

 *

 * @ingroup Patternist_functions

 */

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist

{

    /**

     * @short Implements the function <tt>fn:count()</tt>.

     *

     * @ingroup Patternist_functions

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

     */

    class CountFN : public FunctionCall

    {

    public:

        virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;

        /**

         * If @p reqType is CommonSequenceTypes::EBV, this function call is rewritten

         * into a call to <tt>fn:exists()</tt>. Hence, <tt>if(count(X)) then ...</tt> is

         * rewritten into <tt>if(exists(X)) then ...</tt>.

         */

        virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,

                                          const SequenceType::Ptr &reqType);

        /**

         * If CountFN's operand has a Cardinality that is exact, as per Cardinality::isExact(),

         * it is rewritten to the Cardinality's count.

         */

        virtual Expression::Ptr compress(const StaticContext::Ptr &context);

    };

    /**

     * @short Base class for the implementations of the <tt>fn:avg()</tt> and <tt>fn:sum()</tt> function.

     *

     * @ingroup Patternist_functions

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

     */

    class AddingAggregate : public FunctionCall

    {

    public:

        virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,

                                          const SequenceType::Ptr &reqType);

    protected:

        AtomicMathematician::Ptr m_mather;

    };

    /**

     * @short Implements the function <tt>fn:avg()</tt>.

     *

     * @ingroup Patternist_functions

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

     */

    class AvgFN : public AddingAggregate

    {

    public:

        virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;

        virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,

                                          const SequenceType::Ptr &reqType);

        virtual SequenceType::Ptr staticType() const;

    private:

        AtomicMathematician::Ptr m_adder;

        AtomicMathematician::Ptr m_divider;

    };

    /**

     * @short Implements the function <tt>fn:sum()</tt>.

     *

     * @ingroup Patternist_functions

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

     */

    class SumFN : public AddingAggregate

    {

    public:

        virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;

        virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,

                                          const SequenceType::Ptr &reqType);

        virtual SequenceType::Ptr staticType() const;

    };

}

QT_END_NAMESPACE

QT_END_HEADER

#endif