[swift-evolution] [Pitch] Allow use of the name "default" for enum cases and function names

Vladimir.S svabox at gmail.com
Mon Jun 20 08:00:34 CDT 2016

Also didn't know `case _: ` works as `default`. So we have 2 things that do 
exactly the same. Agree, that leaving `case _:` and removing 'default' will 
increase the consistency of the language. I even think `case _:` is better 
than `default` in any way. Don't agree that this case confuse anybody : 
each language has its own special syntax features. If one will teach Swift 
as first language - no problems at all, `case _: ` construction is very 
simple and understandable. If one will teach Swift as next language, so 
this person is professional enough to use `case _:` in Swift instead of 
`default`, don't see any tragedy here.
But yes, I see that this is "commonly rejected proposal", so OK.

On 17.06.2016 23:54, Tony Allevato via swift-evolution wrote:
> Agreed, it sounds like default should be treated as a contextual keyword in
> this case.
> It never even occurred to me that "case _:" would work as a replacement for
> default, but it does even today—and now that I've seen it, it makes total
> sense. I could definitely get behind a proposal to remove "default" as a
> keyword from the language entirely in favor of that. It blends well with
> other pattern matching. The only concern I would have would be about
> discoverability, but it would be easy to have the compiler emit an error
> when it sees default in a switch: "default is unsupported; use case _ instead."
> On Fri, Jun 17, 2016 at 1:45 PM E. Maloney via swift-evolution
> <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>     While upgrading to Swift 3, I noticed that I had a few enums with cases
>     named .Default that, after being converted to lowercase, now need to be
>     rendered using the ugly .`default` notation.
>     I also noticed something similar while reading the docs for
>     NotificationCenter (the NSNotificationCenter replacement, that is, not
>     the NotificationCenter that governs the notification center UI);
>     “default” can’t be used as a function name without escaping, so the
>     declaration is:
>     class func `default`()
>     It seems to me that in the case of function names and enum cases, the
>     parser should be able to unambiguously distinguish between the Swift
>     keyword “default” and a user-defined name “default”, since IIRC the
>     keyword “default” can only be used in parameter lists for generated
>     headers and as the last item in a switch statement.
>     (Perhaps this is also another argument in favor of using “case _:” in
>     place of “default:” in a switch statement.)
>     What do you think? Is there any reason this *wouldn’t* be feasible?
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