> Is this what you're trying to achieve, only using a nicer syntax to > represent it? > http://swiftlang.ng.bluemix.net/#/repl/57fb8ac27365890cc848f831
Yes This similar to example shown in my original email, where struct is used as a rawType and custom string literal parsing to assign values to enum cases. http://swiftlang.ng.bluemix.net/#/repl/57fb8e3e4f9bcf25fdd415cd What I would like to achieve is (more or less) http://swiftlang.ng.bluemix.net/#/repl/57fb98074f9bcf25fdd415d8 regards -- | Mateusz Malczak 2016-10-10 14:35 GMT+02:00 Jay Abbott <j...@abbott.me.uk>: > Is this what you're trying to achieve, only using a nicer syntax to > represent it? > http://swiftlang.ng.bluemix.net/#/repl/57fb8ac27365890cc848f831 > > > On Mon, 10 Oct 2016 at 13:04 Mateusz Malczak <mate...@malczak.info> wrote: >> >> I think, I have used quite unfortunate naming, which is a root of an >> misunderstanding here. By saying 'enums with stored properties' what I >> was really thinking about, was enumeration type with stored constant, >> immutable properties (constants). I don't want to duplicate 'struct' >> type here, but instead I would like to make it possible to store a >> const values in enumeration cases. So going back to my example once >> again: >> >> Lest define an enumeration type `Format` with 3 possible cases. Each >> case will be able to carry over some additional information - in this >> case a pair of numbers (but in fact Any? should be possible) >> >> enum Format { >> case SMALL(30, 30) >> case MEDIUM(60, 60) >> case LARGE(120, 120) >> var width: Double >> var height: Double >> init(width: Double, height: Double) { >> self.width = width >> self.height = height >> } >> } >> >> I'm not sure about 'var' clause in that example as it causes all the >> confusion. >> >> I can access additional info stored in enum case, but it cannot be >> modified. Format.SMALL doesn't change, as well as non of its >> properties. >> >> // allowed usage >> let format = Format.SMALL >> let width = format.width // this would be equal to 30 (const value >> assigned to 'width' property on enum case .SMALL) >> >> // not allowed usage >> let format = Format.SMALL >> format.width = 40 // error, stored values are immutable and can not be >> modified >> >> We get all advantages of enumeration type, and, assuming all cases are >> describing the same possible state, we can store some extra >> information in each case. This can be called a third enumeration type >> feature, right next to associated values and rawType. >> >> -- >> | Mateusz Malczak >> >> >> 2016-10-10 13:40 GMT+02:00 Jay Abbott <j...@abbott.me.uk>: >> > Thanks for the explanation Mateusz, I think I understand. So the enum >> > still >> > only has 3 cases, SMALL, MEDIUM, and LARGE, but an instance also has >> > some >> > properties? >> > >> > So some code to use it might be: >> > var aFormat = Format.LARGE >> > aFormat.width = 150 // aFormat is still Format.LARGE - this doesn't >> > change >> > >> > Is that right? >> > >> > On Mon, 10 Oct 2016 at 09:06 Mateusz Malczak via swift-evolution >> > <swift-evolution@swift.org> wrote: >> >> >> >> Hi, >> >> > Perhaps it is a bit ugly, but I don’t know if allowing stored >> >> > properties >> >> > on >> >> > enums is the solution: that looks very ugly to me too. >> >> >> >> That may look ugly, but can be very useful, if only you think >> >> rawValue's are useful then you should also agree that stored >> >> properties would be useful :) >> >> >> >> -- >> >> | Mateusz Malczak >> >> >> >> >> >> 2016-10-10 9:26 GMT+02:00 David Hart via swift-evolution >> >> <swift-evolution@swift.org>: >> >> > Perhaps it is a bit ugly, but I don’t know if allowing stored >> >> > properties >> >> > on >> >> > enums is the solution: that looks very ugly to me too. >> >> > >> >> > On 10 Oct 2016, at 02:36, Erica Sadun via swift-evolution >> >> > <swift-evolution@swift.org> wrote: >> >> > >> >> > I would love to be able to have stored properties in addition to the >> >> > varying >> >> > elements. >> >> > >> >> > Now, I end up creating a secondary struct T and doing case a(T, >> >> > whatever), >> >> > b(T, whatever), c(T, whatever), etc. where the same associated >> >> > structure >> >> > is >> >> > every case, *or* I end up putting the enum into a struct which means >> >> > the >> >> > guiding semantics are the struct and not the enumeration. Both >> >> > approaches >> >> > are ugly. >> >> > >> >> > -- E >> >> > >> >> > On Oct 9, 2016, at 6:03 PM, Jay Abbott via swift-evolution >> >> > <swift-evolution@swift.org> wrote: >> >> > >> >> > Mateusz, >> >> > >> >> > To me, "Enumeration defines a type with well defined set of possible >> >> > values" >> >> > seems to contradict the idea of having properties that can have >> >> > different >> >> > values. What could you do with this special enum - what would the >> >> > code >> >> > that >> >> > uses it look like? >> >> > >> >> > >> >> > >> >> > On Sun, 9 Oct 2016 at 04:56 Robert Widmann via swift-evolution >> >> > <swift-evolution@swift.org> wrote: >> >> >> >> >> >> I’ve started doing this to try and mimic “Smart Constructors” in >> >> >> Haskell >> >> >> and I think it works quite well. >> >> >> >> >> >> struct Format { >> >> >> enum FormatBacking { >> >> >> case SMALL(Int, Int) >> >> >> case MEDIUM(Int, Int) >> >> >> case LARGE(Int, Int) >> >> >> } >> >> > >> >> > >> >> > _______________________________________________ >> >> > swift-evolution mailing list >> >> > swift-evolution@swift.org >> >> > https://lists.swift.org/mailman/listinfo/swift-evolution >> >> > >> >> > >> >> > >> >> > _______________________________________________ >> >> > swift-evolution mailing list >> >> > swift-evolution@swift.org >> >> > https://lists.swift.org/mailman/listinfo/swift-evolution >> >> > >> >> _______________________________________________ >> >> swift-evolution mailing list >> >> swift-evolution@swift.org >> >> https://lists.swift.org/mailman/listinfo/swift-evolution _______________________________________________ swift-evolution mailing list swift-evolution@swift.org https://lists.swift.org/mailman/listinfo/swift-evolution