[swift-evolution] List of all Enum values (for simple enums)

[Jacob Bandes-Storch]

Would this work with enums imported from C/Obj-C code as well? Personally,
I've worked with code that would benefit greatly from it. But I could
imagine confusion if a C enum already defines "max" or "number of elements"
as a member of the enum, and Swift imports .max as being one greater.

Jacob

On Wed, Dec 9, 2015 at 10:19 AM, David Waite <david at alkaline-solutions.com>
wrote:

> There are a number of possible proposals for enhancements I see off the
> bat for “basic" enums (without associated data):
>
> 1. A generated implementation of SequenceType based on declaration order
> 2. A second interface or extension to the enum type could supply static
> max and min properties when the RawValue is Comparable
> 3. For enums with a String raw value, CustomStringConvertible and
> Streamable might make sense as well. You would likely want
> CustomDebugStringConvertible to also be defined to supply the original
> type-based value.
>
> -DW
>
> On Dec 8, 2015, at 11:13 PM, Chris Lattner via swift-evolution <
> swift-evolution at swift.org> wrote:
>
>
> On Dec 8, 2015, at 10:09 PM, Jacob Bandes-Storch <jtbandes at gmail.com>
> wrote:
>
> Do you have any recommendations for where in the compiler this would
> happen, for those of us without thorough knowledge of all parts? What would
> the team need to see in a proposal for it to be sufficiently complete?
>
>
> This would slot into the same logic that synthesizes memberwise
> initializers on structs.  That said, I think that hashing out the right
> user model and set of capabilities is the first place to start.
>
> -Chris
>
>
> On Tue, Dec 8, 2015 at 10:05 PM Chris Lattner <clattner at apple.com> wrote:
>
>>
>> > On Dec 8, 2015, at 9:53 PM, Jacob Bandes-Storch via swift-evolution <
>> swift-evolution at swift.org> wrote:
>> >
>> > Enums are often used without associated values:
>> >
>> >     enum Attribute { case Title, Date }
>> >     enum Style { case Dark, Light }
>> >
>> > In such cases, it's very useful to be able to iterate over all possible
>> values. But you have to do it manually:
>> >
>> >     extension Attribute {
>> >         static var allValues: [Attribute] {
>> >             return [.Title, .Date]  // imagine this x100, and not
>> autogenerated :(
>> >         }
>> >     }
>> >
>> > It would be nice if the compiler generated this for us. It doesn't have
>> to be an Array, but any kind of SequenceType. Maybe something like
>> "StaticCollection". Of course, this doesn't work in the general case, but I
>> think simple enums are common enough that it might be worth doing.
>>
>> This is a commonly requested feature, and tons of people would support
>> the ability to do this somehow.  Similarly, for integer-backed enums, many
>> people want to be able to know the “max” enum rawValue so they can index
>> into them.
>>
>> -Chris
>>
>>
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