[swift-evolution] ternary operator ?: suggestion

[Craig Cruden]

Paul, 

I tried to put my understanding on the latest proposal option into a draft on github (instead of my usual BitBucket repo).  

Take a look at it and see if there is anything useable.

https://github.com/cacruden/swift-evolution/blob/master/proposals/0000-Pattern-Matching-Partial-Function.md <https://github.com/cacruden/swift-evolution/blob/master/proposals/0000-Pattern-Matching-Partial-Function.md>

Craig

> On 2016-01-11, at 14:17:09, Craig Cruden <ccruden at novafore.com> wrote:
> 
> Ignore the last comment - tired and mistaken. :p
> 
> 
>> On 2016-01-11, at 14:16:01, Craig Cruden <ccruden at novafore.com <mailto:ccruden at novafore.com>> wrote:
>> 
>> I just realized “cases” probably is not needed - if it see’s a comma after case but before “:” then it is the concise form.  
>> 
>> If the switch / case can do that , the partial function case should be able to do the same thing.
>> 
>> 
>>> On 2016-01-11, at 13:23:19, Craig Cruden <ccruden at novafore.com <mailto:ccruden at novafore.com>> wrote:
>>> 
>>> I have thought about it a bit more and I think this would cover all the cases that interest me (in addition to others needs for a little more conciseness on the most simple case).  
>>> 
>>> I also think we need to be clear that the “case” (or cases) and “default” are is really just a partial function which in it’s entirety is really just a complete function for used wherever a complete function (exhaustive) can be passed (e.g. reduce, filter, etc.) - otherwise they might get confused on why we are adding it to “map”.  
>>> 
>>> The optional where clause should also be part of the case clause as part of the proposal.  
>>> 
>>> There would be no need for statement based “fallthrough”.
>>> 
>>> You mentioned your proposal….  have you drafted a formal proposal draft?
>>> 
>>> 
>>> 
>>>> On 2016-01-10, at 12:41:03, Paul Ossenbruggen via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>>>> 
>>>> I agree that it would be really useful to keep things concise. I am going to suggest again an idea I had in the past, it is also in my proposal, which might work well for this problem. This might address the verbosity of the “case” and at the same time make it obvious we are dealing with a switch expression. So both would be valid: 
>>>> 
>>>> 	let num = color.map {
>>>> 		cases   .Red: 100, 
>>>> 			     .Green:  200, 
>>>> 			     .Blue: 300
>>>> 		default: -1 
>>>> 	}
>>>> 	let num = color.map {
>>>> 		case     .Red: 100
>>>> 		case     .Green:  200 
>>>> 		case     .Blue: 300
>>>> 		default: -1 
>>>> 	}
>>>> 
>>> 
>> 
> 

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