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secondo/Algebras/CRel/Operators/ApplyPredicate.h

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2026-01-23 17:03:45 +08:00
/*
----
This file is part of SECONDO.
Copyright (C) 2004-2009, University in Hagen, Faculty of Mathematics
and Computer Science, Database Systems for New Applications.
SECONDO is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
SECONDO is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with SECONDO; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
----
*/
#pragma once
#include "AlgebraTypes.h"
#include "NestedList.h"
#include "Operator.h"
#include "StandardTypes.h"
namespace CRelAlgebra
{
namespace Operators
{
/*
Operator implementation of the 'apply' operator.
This operator determines the indices of entries in a array of attributes
which satisfy a given predicate.
The Operator expects two parameters.
The first parameter represents the array and must be of type 'attrarray'.
The second parameter represents the predicate and must be a function
evaluating from the array's attribute-type to 'bool'.
The returned value represents the determined indices and is of type
'longints'.
*/
class ApplyPredicate : public Operator
{
public:
ApplyPredicate();
private:
static const OperatorInfo info;
static ValueMapping valueMappings[];
static ListExpr TypeMapping(ListExpr args);
static int SelectValueMapping(ListExpr args);
static int AttrArrayValueMapping(ArgVector args, Word &result,
int message, Word &local, Supplier s);
static int TBlockValueMapping(ArgVector args, Word &result,
int message, Word &local, Supplier s);
};
}
}