It seems that someone needed an optimized factorial-routine… The problem on the other hand is, that the machine friendly code is much less „didactical" than the human friendly common implementation. To have both I propose to add the human friendly clear and short version as comment. Its a bit like some primitive methods were after the primitive call there is the smalltalk version as well (VisualWorks).
Regards, Bernhard Höfner > ... > The algos are different: > > Pharo 8: > Integer>>factorial > "Answer the factorial of the receiver." > > self = 0 ifTrue: [^ 1]. > self > 0 ifTrue: [^ self * (self - 1) factorial]. > self error: 'Not valid for negative integers' > > > Pharo 9: > > Integer>>factorial > | nex nexnext acc | > "Guard for know cases (0,1,2,error)" > self < 3 > ifTrue: [ ^ self < 0 > ifTrue: [ > self error: 'Not valid for negative integers' ] > ifFalse: [ > self > 0 > > ifTrue: [ self ] > > ifFalse: [ 1 ] ] ]. > acc := 2. > nex := 2. > nexnext := 10. > > self // 2 - 1 > timesRepeat: [ nex := nex + nexnext. > nexnext := nexnext + 8. > acc := acc * nex ]. > self odd > ifTrue: [ acc := acc * self ]. > ^ acc > > ...
