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1.197.9 UndefinedObject: testing

ifNil: nilBlock
Evaluate nilBlock if the receiver is nil, else answer nil


ifNil: nilBlock ifNotNil: notNilBlock
Evaluate nilBlock if the receiver is nil, else evaluate notNilBlock, passing the receiver.


ifNotNil: notNilBlock
Evaluate notNilBlock if the receiver is not nil, passing the receiver. Else answer nil


ifNotNil: notNilBlock ifNil: nilBlock
Evaluate nilBlock if the receiver is nil, else evaluate notNilBlock, passing the receiver.


isNil
Answer whether the receiver is the undefined object nil. Always answer true.


isNull
Answer whether the receiver represents a NULL C pointer. Always answer true.


notNil
Answer whether the receiver is not the undefined object nil. Always answer false.