Hi, I'm a little surprised with the current SortedCollection #= implementation... it is: = aSortedCollection "Answer true if my and aSortedCollection's species are the same, and if our blocks are the same, and if our elements are the same." self species = aSortedCollection species ifFalse: [^ false]. sortBlock = aSortedCollection sortBlock ifTrue: [^ super = aSortedCollection] ifFalse: [^ false] and my surprise is because it compares the sortBlocks that makes the simplest case to fail like this one: (SortedCollection sortBlock: [ :a :b | a < b ]) = (SortedCollection sortBlock: [ :a :b | a < b ]) One could argue that if we remove the sortBlock comparison then : (SortedCollection sortBlock: [ :a :b | a < b ]) = (SortedCollection sortBlock: [ :a :b | a > b ]) would return true... but is that wrong? ... or is the philosophy to use the message #hasEqualElements: on this cases? BTW, VisualWorks implementation is the same as pharo, but the BlockClosure>>= is different and that's why it works as at least I expected :-) Bye, Hernan -- *Hernán Wilkinson Agile Software Development, Teaching & Coaching* *Phone: +54 - 011 - *6091 - 3125* Mobile: +54 - 911 - 4470 - 7207 email: hernan.wilkinson@10Pines.com site: http://www.10Pines.com <http://www.10pines.com/>* Address: Alem 693, Floor 5 B, Buenos Aires, Argentina