casacore::TaQLNodeHandler Class Reference

Class to handle the nodes in the raw TaQL parse tree. More...

#include <TaQLNodeHandler.h>

Inheritance diagram for casacore::TaQLNodeHandler:

Public Member Functions
virtual	~TaQLNodeHandler ()
TaQLNodeResult	handleTree (const TaQLNode &tree, const std::vector< const Table * > &)
	Handle and process the raw parse tree.
virtual TaQLNodeResult	visitConstNode (const TaQLConstNodeRep &node)
	Define the functions to visit each node type.
virtual TaQLNodeResult	visitRegexNode (const TaQLRegexNodeRep &node)
virtual TaQLNodeResult	visitUnaryNode (const TaQLUnaryNodeRep &node)
virtual TaQLNodeResult	visitBinaryNode (const TaQLBinaryNodeRep &node)
virtual TaQLNodeResult	visitMultiNode (const TaQLMultiNodeRep &node)
virtual TaQLNodeResult	visitFuncNode (const TaQLFuncNodeRep &node)
virtual TaQLNodeResult	visitRangeNode (const TaQLRangeNodeRep &node)
virtual TaQLNodeResult	visitIndexNode (const TaQLIndexNodeRep &node)
virtual TaQLNodeResult	visitKeyColNode (const TaQLKeyColNodeRep &node)
virtual TaQLNodeResult	visitTableNode (const TaQLTableNodeRep &node)
virtual TaQLNodeResult	visitColNode (const TaQLColNodeRep &node)
virtual TaQLNodeResult	visitColumnsNode (const TaQLColumnsNodeRep &node)
virtual TaQLNodeResult	visitJoinNode (const TaQLJoinNodeRep &node)
virtual TaQLNodeResult	visitGroupNode (const TaQLGroupNodeRep &node)
virtual TaQLNodeResult	visitSortKeyNode (const TaQLSortKeyNodeRep &node)
virtual TaQLNodeResult	visitSortNode (const TaQLSortNodeRep &node)
virtual TaQLNodeResult	visitLimitOffNode (const TaQLLimitOffNodeRep &node)
virtual TaQLNodeResult	visitGivingNode (const TaQLGivingNodeRep &node)
virtual TaQLNodeResult	visitUpdExprNode (const TaQLUpdExprNodeRep &node)
virtual TaQLNodeResult	visitSelectNode (const TaQLSelectNodeRep &node)
virtual TaQLNodeResult	visitUpdateNode (const TaQLUpdateNodeRep &node)
virtual TaQLNodeResult	visitInsertNode (const TaQLInsertNodeRep &node)
virtual TaQLNodeResult	visitDeleteNode (const TaQLDeleteNodeRep &node)
virtual TaQLNodeResult	visitCountNode (const TaQLCountNodeRep &node)
virtual TaQLNodeResult	visitCalcNode (const TaQLCalcNodeRep &node)
virtual TaQLNodeResult	visitCreTabNode (const TaQLCreTabNodeRep &node)
virtual TaQLNodeResult	visitColSpecNode (const TaQLColSpecNodeRep &node)
virtual TaQLNodeResult	visitRecFldNode (const TaQLRecFldNodeRep &node)
virtual TaQLNodeResult	visitUnitNode (const TaQLUnitNodeRep &node)
virtual TaQLNodeResult	visitAltTabNode (const TaQLAltTabNodeRep &node)
virtual TaQLNodeResult	visitAddColNode (const TaQLAddColNodeRep &node)
virtual TaQLNodeResult	visitSetKeyNode (const TaQLSetKeyNodeRep &node)
virtual TaQLNodeResult	visitRenDropNode (const TaQLRenDropNodeRep &node)
virtual TaQLNodeResult	visitAddRowNode (const TaQLAddRowNodeRep &node)
virtual TaQLNodeResult	visitConcTabNode (const TaQLConcTabNodeRep &node)
virtual TaQLNodeResult	visitShowNode (const TaQLShowNodeRep &node)
Static Public Member Functions
static const TaQLNodeHRValue &	getHR (const TaQLNodeResult &)
	Get the actual result object from the result.
Private Member Functions
TableParseSelect *	pushStack (TableParseSelect::CommandType)
	Push a new TableParseSelect on the stack.
TableParseSelect *	topStack () const
	Get the top of the TableParseSelect stack.
void	popStack ()
	Pop the top from the TableParseSelect stack.
void	clearStack ()
	Clear the select stack.
TaQLNodeResult	handleSelect (const TaQLSelectNodeRep &node, Bool doExec)
	Handle the select command.
void	handleTables (const TaQLMultiNode &)
	Handle a MultiNode containing table info.
Table	makeConcatTable (const TaQLMultiNodeRep &node)
	Make a ConcatTable from a nested set of tables.
void	handleWhere (const TaQLNode &)
	Handle the WHERE clause.
void	handleHaving (const TaQLNode &)
	Handle the HAVING clause.
void	handleUpdate (const TaQLMultiNode &)
	Handle the UPDATE SET clause.
void	handleInsCol (const TaQLMultiNode &)
	Handle the INSERT columns.
void	handleInsVal (const TaQLNode &)
	Handle the INSERT values.
void	handleColSpecs (const TaQLMultiNode &)
	Handle a column specification in a create table.
Record	handleMultiRecFld (const TaQLNode &node)
	Handle a Multi RecFld representing a Record.
Private Attributes
std::vector< TableParseSelect * >	itsStack
std::vector< const Table * >	itsTempTables

Detailed Description

Class to handle the nodes in the raw TaQL parse tree.

Intended use:

Internal

Review Status

Test programs:: tTableGram

Prerequisite

TaQLNode
Note 199 describing TaQL

Synopsis

TaQLNodeHandler is a specialization of class TaQLNodeVisitor . It processes the raw TaQL parse tree generated by TableGram. The processing is done in a recursive way. It starts at the top (which is a SELECT, UPDATE, etc. expression) and the processing results of a query are stored in a TableParseSelect object. These objects are kept in a stack for possible nested queries. After a query is fully processed, it is executed. Usually the result is a table; only a CALC command gives a TableExprNode as result.

Motivation

Separating the raw query parsing from the query processing has several advantages compared to the old situation where parsing and processing were combined.

The full command is parsed before any processing is done. So in case of a parse error, no possibly expensive processing has been done yet.
In the future query optimization can be done in an easier way.
Nested parsing is not possible. In case a Table is opened with a virtual TaQL column, the parsing of that TaQL string does not interfere with parsing the TaQL command.
It is possible to use expressions in the column list. That could not be done before, because the column list was parsed/processed before the table list.

Definition at line 95 of file TaQLNodeHandler.h.

Constructor & Destructor Documentation

virtual casacore::TaQLNodeHandler::~TaQLNodeHandler ( ) [virtual]

Member Function Documentation

void casacore::TaQLNodeHandler::clearStack ( ) [private]

Clear the select stack.

const TaQLNodeHRValue & casacore::TaQLNodeHandler::getHR ( const TaQLNodeResult & res ) [inline, static]

Get the actual result object from the result.

Definition at line 315 of file TaQLNodeHandler.h.

References casacore::TaQLNodeResult::getRep().

void casacore::TaQLNodeHandler::handleColSpecs ( const TaQLMultiNode & ) [private]

Handle a column specification in a create table.

void casacore::TaQLNodeHandler::handleHaving ( const TaQLNode & ) [private]

Handle the HAVING clause.

void casacore::TaQLNodeHandler::handleInsCol ( const TaQLMultiNode & ) [private]

Handle the INSERT columns.

void casacore::TaQLNodeHandler::handleInsVal ( const TaQLNode & ) [private]

Handle the INSERT values.

Record casacore::TaQLNodeHandler::handleMultiRecFld ( const TaQLNode & node ) [private]

Handle a Multi RecFld representing a Record.

TaQLNodeResult casacore::TaQLNodeHandler::handleSelect	(	const TaQLSelectNodeRep &	node,
		Bool	doExec
	)			`[private]`

Handle the select command.

Optionally the command is not executed (needed for the EXISTS operator).

void casacore::TaQLNodeHandler::handleTables ( const TaQLMultiNode & ) [private]

Handle a MultiNode containing table info.

TaQLNodeResult casacore::TaQLNodeHandler::handleTree	(	const TaQLNode &	tree,
		const std::vector< const Table * > &
	)

Handle and process the raw parse tree.

The result contains a Table or TableExprNode object.

void casacore::TaQLNodeHandler::handleUpdate ( const TaQLMultiNode & ) [private]

Handle the UPDATE SET clause.

void casacore::TaQLNodeHandler::handleWhere ( const TaQLNode & ) [private]

Handle the WHERE clause.

Table casacore::TaQLNodeHandler::makeConcatTable ( const TaQLMultiNodeRep & node ) [private]

Make a ConcatTable from a nested set of tables.

void casacore::TaQLNodeHandler::popStack ( ) [private]

Pop the top from the TableParseSelect stack.

TableParseSelect* casacore::TaQLNodeHandler::pushStack ( TableParseSelect::CommandType ) [private]

Push a new TableParseSelect on the stack.

TableParseSelect* casacore::TaQLNodeHandler::topStack ( ) const [private]

Get the top of the TableParseSelect stack.

virtual TaQLNodeResult casacore::TaQLNodeHandler::visitAddColNode ( const TaQLAddColNodeRep & node ) [virtual]

casacore::TaQLNodeHandler Class Reference

Public Member Functions

Static Public Member Functions

Private Member Functions

Private Attributes