void Command_Table_AddColumn(AddColumnDialog.Result result)
		{
			var table = GetTable();
			var variables = GetTableVariables(table);
			var results = new NEExpression(result.Expression).EvaluateRows<string>(variables, table.NumRows);
			table.AddColumn(result.ColumnName, results);
			SetText(table);
		}
		static public Result Run(Window parent, NEVariables variables, int numRows)
		{
			var dialog = new AddColumnDialog(variables, numRows) { Owner = parent };
			return dialog.ShowDialog() ? dialog.result : null;
		}