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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_DocumentFN_H

#define Patternist_DocumentFN_H

#include "qfunctioncall_p.h"

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist

{

    /**

     * @short Implements XSL-T's function <tt>fn:document()</tt>.

     *

     * @c fn:document() has no evaluation functions, because it rewrites

     * itself to a set of expressions that is the implementation.

     *

     * The two-argument version:

     *

     * <tt>document($uris as item()*, $baseURINode as node()) as node()*</tt>

     *

     * is rewritten into:

     *

     * <tt>for $uri in distinct-values($uris)

     * return doc(resolve-uri($uri, base-uri($baseURINode)))</tt>

     *

     * and the single version argument:

     *

     * <tt>document($uris as item()*) as node()*</tt>

     *

     * is rewritten into:

     *

     * <tt>for $uri in distinct-values($uris)

     * return doc($uri)</tt>

     *

     * The distinct-values() call ensures the node deduplication and sorting,

     * although it fails in the case that URIs resolve/directs in some way to

     * the same document. Some of those cases can be solved by wrapping the

     * whole expression with a node deduplication(conceptually the-for-loop/.).

     * One advantage with distinct-values() over generating traditional node

     * sorting/deduplication code is that the latter contains node sorting

     * which is uecessary and can be hard to analyze away. distinct-values()

     * doesn't have this problem due to its narrower task..

     *

     * This works without problems, assuming XTRE1160 is not raised and that

     * the recover action instead is ignore. In the case XTRE1160 is raised,

     * one must cater for this.

     *

     * In addition to this, both signatures has its first argument changed to

     * type <tt>xs:string*</tt>, in order to generate atomization code.

     *

     * One notable thing is that the expression for $baseURINode, is moved

     * inside a loop, and will be evaluated repeatedly, unless moved out as

     * part of optimization.

     *

     * @ingroup Patternist_functions

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

     * @since 4.5

     */

    class DocumentFN : public FunctionCall

    {

    public:

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

                                          const SequenceType::Ptr &reqType);

    };

}

QT_END_NAMESPACE

QT_END_HEADER

#endif