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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_Literal_H

#define Patternist_Literal_H

#include "qemptycontainer_p.h"

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist

{

    /**

     * @short Houses an AtomicValue, making it available as an Expression.

     *

     * This is not only literals that can be created via the XQuery syntax(strings and numbers), but

     * all other atomic values, such as <tt>xs:date</tt> or <tt>xs:time</tt>.

     *

     * @see <a href="http://www.w3.org/TR/xquery/#id-literals">XQuery 1.0: An XML Query Language,

     * 3.1.1 Literals</a>

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

     * @ingroup Patternist_expressions

     */

    class Literal : public EmptyContainer

    {

    public:

        /**

         * Creates a Literal that represents @p item.

         *

         * @param item must be non-null and cannot be a QXmlNodeModelIndex.

         */

        Literal(const Item &item);

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

        virtual bool evaluateEBV(const DynamicContext::Ptr &context) const;

        void evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const;

        virtual SequenceType::Ptr staticType() const;

        virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const;

        virtual ID id() const;

        virtual QString description() const;

        /**

         * @returns Expression::DisableElimination and Expression::IsEvaluated

         */

        virtual Properties properties() const;

        /**

         * Declaring the return value of this function a const reference, leads

         * to crashes in patternistview, for a to me unknown reason.

         */

        inline Item item() const

        {

            return m_item;

        }

    private:

        const Item m_item;

    };

    /**

     * @short Creates a Literal that wraps @p item, and returns it.

     *

     * This simplifies code. Instead of writing:

     *

     * @code

     * Expression::Ptr(new Literal(item));

     * @endcode

     *

     * One can write:

     *

     * @code

     * wrapLiteral(item);

     * @endcode

     *

     * This function is not declared static, because it breaks the build on

     * at least aix-xlc-64.

     *

     * @relates Literal

     */

    inline Expression::Ptr wrapLiteral(const Item &item,

                                       const StaticContext::Ptr &context,

                                       const SourceLocationReflection *const r)

    {

        Q_ASSERT(item);

        const Expression::Ptr retval(new Literal(item));

        context->addLocation(retval.data(), context->locationFor(r));

        return retval;

    }

}

QT_END_NAMESPACE

QT_END_HEADER

#endif