Noury also proposed a trait to avoid to systematically have to implement hash. Vitor why don't you take it as a small project to propose a solution for Pharo.
On Thu, Oct 5, 2017 at 6:34 PM, Vitor Medina Cruz <vitormc...@gmail.com> wrote: > Yes, canEqual implementation also make #= be commutative. > > On Tue, Oct 3, 2017 at 11:11 AM, Denis Kudriashov <dionisi...@gmail.com> > wrote: >> >> >> 2017-10-02 17:30 GMT+02:00 Denis Kudriashov <dionisi...@gmail.com>: >>> >>> >>> 2017-10-02 17:13 GMT+02:00 Vitor Medina Cruz <vitormc...@gmail.com>: >>>> >>>> I am sorry, not species, but #isKindOf istead of #= to compare classes. >>> >>> >>> It is bad idea. #= should be transitive. >> >> >> Oh, I used wrong word, shame on me :). I tried to say commutative. >> >>> >>> How you will generate it with isKindOf: logic? You need to know common >>> parent. >>> >>> Also I not remember cases where I was needed two instances of different >>> classes to be equal. >>> And I can imaging the problems which it will lead to. >>> >>>> >>>> >>>> On Mon, Oct 2, 2017 at 11:57 AM, Denis Kudriashov <dionisi...@gmail.com> >>>> wrote: >>>>> >>>>> >>>>> 2017-10-02 16:37 GMT+02:00 Sean P. DeNigris <s...@clipperadams.com>: >>>>>> >>>>>> >>>>>> Two questions/comments about the generated code: >>>>>> 1. #= >>>>>> ... >>>>>> self class = anObject class "should compare #species instead?" >>>>>> ifFalse: [ ^ false ]. >>>>>> ... >>>>>> Typically, I've seen #species instead of #class in the guard >>>>>> statement. >>>>>> Should we change it to that? >>>>> >>>>> >>>>> I doubt that it is important for domain classes. Because I never saw >>>>> the user of #species which is not a kind of Collection. And for >>>>> collections >>>>> this refactoring is not valid anyway. >>>>> >>>>>> >>>>>> >>>>>> >>>>>> 2. #hash >>>>>> ^ var1 hash bitXor: (var2 hash bitXor: var3 hash) >>>>>> Is this implementation always safe? It's what I usually hand roll >>>>>> based on >>>>>> what I've seen, but Andres Valloud wrote a whole (large) book on >>>>>> hashing, so >>>>>> I've always wondered if I was missing something… >>>>>> >>>>>> >>>>>> >>>>>> ----- >>>>>> Cheers, >>>>>> Sean >>>>>> -- >>>>>> Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html >>>>>> >>>>> >>>> >>> >> >
