[swift-evolution] [Proposal] Enums with stored properties

[Mateusz Malczak]

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 at 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 at 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 at 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 at 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)
>>   }
>
>
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