71 lines
2.1 KiB
C
71 lines
2.1 KiB
C
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/*
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----
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This file is part of SECONDO.
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Copyright (C) 2004, University in Hagen, Department of Computer Science,
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Database Systems for New Applications.
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SECONDO is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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SECONDO is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with SECONDO; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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----
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The operator "typeof"[2] accepts one argument of any type and results in a
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type error if executed. The error message states the type of the given
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argument. This is useful during building a complex query.
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*/
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#ifndef ALGEBRAS_NESTEDRELATION2_TYPEOF_H_
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#define ALGEBRAS_NESTEDRELATION2_TYPEOF_H_
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namespace nr2a {
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class TypeOf
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{
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public:
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struct Info : OperatorInfo
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{
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Info()
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{
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name = "typeof";
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signature = "X -> X";
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syntax = "_ typeof";
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meaning = "Cancels the query's execution with an error, whose "
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"message states the operator's input type. Useful for debugging "
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"complex, possibly long running queries.";
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example = "query MyRelation complexFunction typeof complexFunction"
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"count";
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}
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};
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virtual ~TypeOf();
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static ListExpr MapType(ListExpr args);
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static ValueMapping functions[];
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static int SelectFunction(ListExpr args);
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static int MapValue(Word* args, Word& result, int message, Word& local,
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Supplier s);
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static CreateCostEstimation costEstimators[];
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protected:
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private:
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TypeOf(); // Declared, but not defined => Linker error on usage
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};
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} /* namespace nr2a*/
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#endif /* ALGEBRAS_NESTEDRELATION2_TYPEOF_H_*/
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