David, > On 11 Jan 2016, at 10:01, David Allouche <[email protected]> wrote: > > I happened to look at the new code for LayoutFrame>>#hash > > hash > ^self species hash bitXor: > (self leftFraction bitXor: > (self leftOffset bitXor: > (self topFraction bitXor: > (self topOffset bitXor: > (self rightFraction bitXor: > (self rightOffset bitXor: > (self bottomFraction bitXor: > self bottomOffset))))))) > > This is a terrible, terrible way to compute a hash. > > 0 xor 0 = 1 xor 1 = 2 xor 2 = etc. > > NEVER compute hashes with xor, that's wrong, and it causes horrible, hard to > debug, performance bugs down the road.
Yeah, that doesn't look very good ;-) > SequenceableCollection>>#hash looks more like a correct way of doing it. I do > not know what is the correct, efficient way to reuse this logic in > LayoutFrame>>#hash. There is actually a 2 part book just about hashing in Smalltalk: http://www.lulu.com/shop/andres-valloud/hashing-in-smalltalk-theory-and-practice/paperback/product-3788892.html It is said to be very good, I sadly have not yet read it ;-) > By the way, how do you guys do code reviews for code integrated into the core? 'Pharo is yours' which means: if you encounter something odd, you are encouraged to improve it. Maybe first discuss it on the ML. If necessary create an issue. Better provide a fix. Sven
