No, please don't spend time on this. We're not going to change this to return a heavyweight data structure like a Set when a simple structure like and Array will do. In mathematics sets are simpler than ordered collections, but in programming languages the relationship is reversed. In general data structures like Set are only used when they are necessary, such as when you need O(1) checking for inclusion. Since there's no such need here, an array is simpler and better.
On Mon, Dec 28, 2015 at 2:40 AM, Kevin Squire <kevin.squ...@gmail.com> wrote: > Hi Ray, > > You're probably the first person to make this observation. I can see your > point, and I don't really have a strong argument or opinion, really--the > main reason it's sorted is probably because it looks nicer--at least if I > did write that code, that would have been my reasoning. > > If you're up for it, you could change it to create a set and submit a pull > request. No guarantees it gets accepted, but the likelihood increases > significantly over not submitting one. :-) > > Cheers, > Kevin > > > On Sunday, December 27, 2015, Ray Toal <ray.t...@gmail.com> wrote: > >> I'm sure the order won't ever change, but I'd still find it odd if the >> documentation of subtypes were to say >> >> "Returns a list of subtypes, sorted by the name of the subtype" >> >> because, well, what about namespaces? What about all sorts of Unicode >> collation definitions that would have to be a part of such a definition? >> >> Yes, as much as I would like to just assert that the result of calling >> subtypes on Type produces the array [DataType, TypeConstructor, Union] it's >> just not supposed to be an array, even if today we can guarantee that the >> array will be sorted, and it is ridiculously unlikely to change. >> >> I just think of unordered collections as sets. I don't think anyone would >> or should ever write code that takes advantage of the fact that this array >> is sorted, though. :) >> >> Thanks for the responses >> >> Ray >> >> >> On Sunday, December 27, 2015 at 5:10:46 PM UTC-8, Kevin Squire wrote: >>> >>> Thanks for looking and posting (I've been on my phone). I think I might >>> have written that code, actually. ;-) >>> >>> Cheers! >>> Kevin >>> >>> On Sunday, December 27, 2015, Ismael VC <ismael...@gmail.com> wrote: >>> >>>> Kevin I tested in my Win laptop with 0.3.11, 0.4.2, 0.4, 0.5+ also the >>>> same versions in julia box, and the output is deterministically sorted, It >>>> seems this has been the way it works for some time now, then I looked at >>>> the code and it’s indeed sorted (should have done that first! :P ): >>>> >>>> - http://git.io/vEXL9 >>>> >>>> subtypes(m::Module, x::DataType) = sort(collect(_subtypes(m, x)), >>>> by=string) >>>> subtypes(x::DataType) = subtypes(Main, x) >>>> >>>> I would expect a very good reason in order to justify a change for this >>>> now. >>>> >>>> >>>> 2015-12-27 18:06 GMT-06:00 Kevin Squire >>>> >>>>> Ray, thanks for the clarification--makes sense. In fact, for >>>>> introspection code like 'subtypes', performance is probably the wrong >>>>> argument--it's unlikely that it occurs in performance-critical code. I >>>>> think it's really that arrays are just simpler. >>>>> >>>>> One aesthetic change I could imagine would be to have the results >>>>> sorted before returning, which would keep the same data structure, but >>>>> solve your problem, and present the subtypes in a way the user would >>>>> likely >>>>> find more useful. >>>>> >>>>> Ismael, it might be a little brittle to depend on the current order >>>>> (unless it's always sorted now). >>>>> >>>>> Cheers, >>>>> Kevin >>>>> >>>>> >>>>> On Sunday, December 27, 2015, Ismael Venegas Castelló wrote: >>>>> >>>>>> You can just do: >>>>>> >>>>>> @assert subtypes(Type) == [DataType, TypeConstructor, Union] >>>>>> >>>>>> I just tested this: >>>>>> >>>>>> julia> @time for i in 1:1000 >>>>>> @assert subtypes(Type) == [DataType, TypeConstructor, >>>>>> Union] >>>>>> end >>>>>> 3.025415 seconds (767.00 k allocations: 224.075 MB, 0.49% gc time) >>>>>> >>>>>> >>>>>> >>>>>> El sábado, 26 de diciembre de 2015, 12:52:51 (UTC-6), Ray Toal >>>>>> escribió: >>>>>>> >>>>>>> I noticed that >>>>>>> >>>>>>> *julia> **subtypes(Type)* >>>>>>> >>>>>>> *3-element Array{Any,1}:* >>>>>>> >>>>>>> * DataType * >>>>>>> >>>>>>> * TypeConstructor* >>>>>>> >>>>>>> * Union * >>>>>>> >>>>>>> and was wondering if there was any significance in the order of the >>>>>>> subtypes. If not, could the method have produced a Set instead? >>>>>>> >>>>>>> >>>>
