[swift-evolution] Anoymous Enums (Updated)

[David Waite]

Having this work similar to other anonymous types would be an extension to the proposal. 

Other anonymous types can be considered equivalent by their definitions, e.g. (x:Int, y:Int) taken as input from one function can be passed to another. 

E.g. your adjustTemperature function wanted to call a checkSafety(device:DeviceType, [low | medium | high]:temperature) -> Bool function - could it?

what about if adjustTemperature took [low | medium | high | extreme]?

what about adjustTemperature having an internal var lastAdjustment:[low | medium | high] - would that work?

My concern is that there could many reasons to need to switch from shorthand/anonymous syntax to a full enum, and that switch will have the same fragility as changing a function from accepting a tuple to accepting a struct. If passing to another function or assigning to a variable would require a switch to a properly qualified enum, the feature seems not worth its character savings.

And I’m already unsure it is worth its existing character savings, especially once you start documenting the meaning of low / medium / high for other developers, and especially if you now have to do so for multiple functions rather than a single enum declaration.

-DW

> On Feb 22, 2016, at 9:46 AM, Erica Sadun via swift-evolution <swift-evolution at swift.org> wrote:
> 
> 
>> On Feb 22, 2016, at 3:53 AM, Tino Heth via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>> 
>> I'm not sure wether I want to see that feature added, but I think there is a "structural" argument for it:
>> We have anonymous functions (closures) and a (restricted) form of anonymous structs (tuples), so it would be consequent to have a anonymous variant for each fundamental entity in the language.
>> I guess it is to late to establish a unified syntax for all of those, though…
> 
> I like the symmetry with the other anonymous types. This provides a highly focused tweak to Swift, with limited impact, and a measurable benefit to developers. (AKA the "Rule of Lattner")
> 
> Further, the values cannot be assigned to variables or passed as arguments as they have no "type".  I suspect it won't be hard to restrict them for being used with `Any` argument, limiting their use to flags and switch cases. If I'm conceptualizing this correctly, the benefits are clear and the consequences are small.
> 
> -- Erica
> 
>> On Feb 21, 2016, at 11:52 PM, Yong hee Lee via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>> 
>> 
>> please check the link below.
>> 
>> https://gist.github.com/erica/9148e2be916c7fae6f1e <https://gist.github.com/erica/9148e2be916c7fae6f1e>
>> 
> 
> 
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