Refactoring if-chains in Smalltalk without class explosion
self condition1
        ifTrue: [ self actionForCondition1 ]
        ifFalse: [
            self condition2
                ifTrue: [ self actionForCondition2 ]
                ifFalse: [
                    self condition3
                        ifTrue: [ self actionForCondition3 ]
                        ifFalse: [ ....  ] ] ]

anObject isKindOf: aClass

anObject = anotherObject

self condition1
    ifTrue: [ ^ self actionForCondition1 ].
self condition2
    ifTrue: [ ^ self actionForCondition2 ].
self condition3
    ifTrue: [ ^ self actionForCondition3 ].
...

selector = selector1 ifTrue: [ invoke method1 ]
  ifFalse: [ selector= selector2 ifTrue: [ invoke method2 ]
   ifFalse: [...] ]]].