[swift-evolution] Allowing enum extensions to also be able to expand case options

[Edward Valentini]

Existing switch statements would have to be modified to add a default statement.  Additionally enums could be marked final to disallow case option expansion



On Jun 30, 2016, at 16:04, David Sweeris <davesweeris at mac.com> wrote:
> 
> By itself, this would break switch statements, since they have to be exhaustive.
> 
> If anyone has any ideas about how to fix that, I'm all ears.
> 
> - Dave Sweeris
> 
>> On Jun 30, 2016, at 14:58, Edward Valentini via swift-evolution <swift-evolution at swift.org> wrote:
>> 
>> 
>> I am finding myself in a situation where the most elegant "swifty" solution would be to allow enum extensions to add to existing case options.  For example lets say I'm using a library that has the following enum defined: 
>> 
>> enum MyDirection {
>>  case east, west
>> }
>> 
>> My app for example also makes use of north and south, so I would love to be able to write: 
>> 
>> extension MyDirection {
>>  case north,south
>> }
>> 
>> In objective c, one would probably have defined constants like MyDirectionEast etc...  these would probably have been mapped to ints or strings so a consumer of this library could have easily extended this to add additional functionality, but using constants like that is not very "swifty"
>> 
>> I'm curious what the swift community thinks.
>> 
>> Thank you 
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