TaQLResult.h

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// # TaQLResult.h: Class to hold the result of a TaQL command
// # Copyright (C) 2004
// # Associated Universities, Inc. Washington DC, USA.
// #
// # This library is free software; you can redistribute it and/or modify it
// # under the terms of the GNU Library General Public License as published by
// # the Free Software Foundation; either version 2 of the License, or (at your
// # option) any later version.
// #
// # This library 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 Library General Public
// # License for more details.
// #
// # You should have received a copy of the GNU Library General Public License
// # along with this library; if not, write to the Free Software Foundation,
// # Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
// #
// # Correspondence concerning AIPS++ should be addressed as follows:
// #        Internet email: casa-feedback@nrao.edu.
// #        Postal address: AIPS++ Project Office
// #                        National Radio Astronomy Observatory
// #                        520 Edgemont Road
// #                        Charlottesville, VA 22903-2475 USA
 
#ifndef TABLES_TAQLRESULT_H
#define TABLES_TAQLRESULT_H
 
// # Includes
#include <casacore/casa/aips.h>
#include <casacore/tables/TaQL/ExprNode.h>
 
namespace casacore {
 
// <summary>
// Class to hold the result of a TaQL command.
// </summary>
 
// <use visibility=local>
 
// <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="">
// </reviewed>
 
// <prerequisite>
// # Classes you should understand before using this one.
// </prerequisite>
 
// <synopsis>
// The result of a TaQL command can be a Table or a TableExprNode.
// This class holds the actual result.
// </synopsis>
 
// <motivation>
// It is possible to give a TaQL command resulting in a TableExprNode
// to make it possible to make expressions of columns.
// </motivation>
 
// # <todo asof="$DATE:$">
// # A List of bugs, limitations, extensions or planned refinements.
// # </todo>
 
class TaQLResult {
 public:
  // Construct from a Table.
  explicit TaQLResult(const Table& = Table());
 
  // Construct from a TableExprNode.
  explicit TaQLResult(const TableExprNode&);
 
  // Is the result a Table?
  Bool isTable() const { return itsNode.isNull(); }
 
  // Return the result as a TableExprInfo.
  // It throws an exception if it is not a table.
  const Table& table() const;
 
  // Return the result as a TableExprNode.
  // It throws an exception if it is not a TableExprNode.
  TableExprNode node() const;
 
 private:
  Table itsTable;
  TableExprNode itsNode;
};
 
}  // namespace casacore
#endif