On 02.08.2015 15:44, jtuchel [via Smalltalk] wrote: > I'd say it is questonable if SequenceableCollections should be > comparable by default. > > is (a b c) equal or lower than (b a c) ? > Doesn't this depend heavily on what is in the Collection and what the > meaning of the Sequence of two Collections is?
(a b c) = (b a c) if a = b (a b c) < (b a c) if a < b The semantics are well defined. Of course, it depends on what's in collection! That's the point - we compare collections by their content. If some elements are not comparable, we'll get DoesNotUnderstand - expected behavior when comparing non-comparable objects. It's the same story as with equality. > So I'd say there is not much use in putting comparisons into the base > class library, because there is a ton of assumptions about the > Collections in whatever implementation one can imagine. I would assume > that this is the job of some business object that holds objects in a > SequenceableCollection. Don't you think? There is only one assumption - that elements of the first collection are comparable to the elements of the second collection. And I think that we shouldn't multiply entities beyond necessity by creating a class when using simple datastructure would be sufficient. > The fact that other languages provide such an implementation doesn't > mean much to me, to be honest. I choose a SequencableCollection in order > to keep objects in a certain order, nothing more, nothing less. That's why we have methods such as polynomialEval: and asDigitsToPower:do: (and I'm not talking about extension methods) ? > I think it is important to not get "overridden" by the fact that > something is extremely easy to do in Smalltalk. We can easily make bad > mistakes, just because we can. > > Just my 2 cents > > Joachim > > Am 02.08.15 um 14:11 schrieb webwarrior: > > > I was surprised when discovered that in Pharo comparison is not > defined for > > lists, arrays and similar datastructures. > > > > Because in almost every programming language (F#, Python, Javascript > just to > > name few) you can compare lists, arrays, etc. By convention, the > ordering is > > lexicographical, just like in strings. > > > > It took little time to add needed methods to SequencableCollection, > but I > > think its better to have them in core library (core image, or how do you > > call it?). > > > > > > > > -- > > View this message in context: > http://forum.world.st/Comparison-for-SequencableCollection-tp4840704.html > > Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com. -- View this message in context: http://forum.world.st/Comparison-for-SequencableCollection-tp4840704p4840708.html Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.
