[swift-evolution] [Proposal] Allow enumerating cases in enumerations

[Vladimir.S]

On 05.07.2016 13:33, James Campbell via swift-evolution wrote:
> Would love a real life scenario of why you would need this.

Some kind of pre-initialization(for GUI as example) for all possible kinds 
of values, that you should process then (for GUI - let's say add to needed 
list).

>
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> On 4 July 2016 at 02:36, Gabriel Lanata via swift-evolution
> <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>
>     Hello, this has been proposed multiple times before in different ways.
>
>     Link to detailed proposal draft:
>     https://github.com/gabriellanata/swift-evolution/blob/master/proposals/NNNN-allow-enumerating-cases-in-enumerations.md
>
>     It is currently not possible to enumerate through all the possible
>     cases of an enumeration object without adding a hardcoded value or
>     recurring to unsafe workarounds. The proposal is to add a method of
>     obtaining an array or set of all the possible cases natively for
>     enumerations without associated values.
>
>     The proposed solution is to implement a native `.cases` static var for
>     all enumerations without associated values. This would provide a strict
>     type-safe way of enumerating though the possible cases without risking
>     runtime errors. The resulting code is a lot cleaner and less prone to
>     errors caused by forgetting to update the hardcoded values when
>     modifying cases.
>
>     Resulting code:
>
>        enum PokemonType {
>            case Fire, Grass, Water, Wind
>        }
>        for pokemonType in PokemonType.cases {
>            // Do stuff
>        }
>        PokemonType.cases.count // Returns 4
>
>
>     -------
>     Gabriel
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