1.201.6 UndefinedObject: iteration

ifNil: nilBlock ifNotNilDo: iterableBlock

Evaluate nilBlock if the receiver is nil, else evaluate iterableBlock with each element of the receiver (which should be an Iterable).

ifNotNilDo: iterableBlock

Evaluate iterableBlock with each element of the receiver (which should be an Iterable) if not nil. Else answer nil

ifNotNilDo: iterableBlock ifNil: nilBlock

Evaluate nilBlock if the receiver is nil, else evaluate iterableBlock, passing each element of the receiver (which should be an Iterable).