Class ADQLNode

source code

             object --+    
                      |    
utils.autonode.AutoNode --+
                          |
                         ADQLNode

Known Subclasses:

• ColumnBearingNode
• , Comparison
• , FieldInfoedNode
• , FromClause
• , JoinOperator
• , JoinSpecification
• , OffsetSpec
• , QualifiedStar
• , SelectList
• , SubJoin
• , TableName
• , TransparentNode
• , morphpg._PGQS

A node within an ADQL parse tree.

ADQL nodes may be parsed out; in that case, they have individual attributes and are craftily flattened in special methods. We do this for nodes that are morphed.

Other nodes basically just have a children attribute, and their flattening is just a concatenation for their flattened children. This is convenient as long as they are not morphed.

To derive actual classes, define

• the _a_<name> class attributes you need,
• the type (a nonterminal from the ADQL grammar)
• plus bindings if the class handles more than one symbol,
• a class method _getInitKWs(cls, parseResult); see below.
• a method flatten() -> string if you define a parsed ADQLNode.
• a method _polish() that is called just before the constructor is done and can be used to create more attributes. There is no need to call _polish of superclasses.

The _getInitKWs methods must return a dictionary mapping constructor argument names to values. You do not need to manually call superclass _getInitKWs, since the fromParseResult classmethod figures out all _getInitKWs in the inheritance tree itself. It calls all of them in the normal MRO and updates the argument dictionary in reverse order.

The fromParseResult class method additionally filters out all names starting with an underscore; this is to allow easy returning of locals().