> On May 10, 2016, at 8:46 PM, Eduardo Mourey Lopez Ne <[email protected]>
> wrote:
>
> Hi Chris
>
> I do agree that it is incosistent that case works in an if but you can’t
> assign it to a bool.
Not to me. I can understand why you would think about it that way, but the let
in “if let” is not assignable to a bool either. Nor is #available.
-Chris
>
> enum Bar {
> case foo(name: String)
> case notFoo
> case unknownFoo
> }
>
> var xx = Bar.foo(name: "Hello")
>
> if case Bar.foo(let name) = xx where name == "Hello” { //This work ok
> print("Hola")
> }
> var bool = case Bar.foo(let name) = xx where name == “Hello” //But this
> doesn’t ???
>
> //The other problem that I see is that the var “xx” seems to get lost int
> case by having it in the middle
> //I think it will be better to have an alternative keyword for a single case,
> like ‘match’ that allows the variable
> //to be at the begging
>
> //This looks much better
> var bool = xx match Bar.foo(let name) where name == “Hello”
>
>
> Thanks
>> On May 10, 2016, at 10:31 PM, Chris Lattner via swift-evolution
>> <[email protected] <mailto:[email protected]>> wrote:
>>
>>
>>> On May 10, 2016, at 4:33 AM, Sam Dods via swift-evolution
>>> <[email protected] <mailto:[email protected]>> wrote:
>>>
>>> I propose that (case .Foo = bar) should be treated as an expression with a
>>> Boolean value, so the result can be set to a variable or returned from a
>>> method.
>>
>> I agree that this is an important use case that Swift doesn’t serve well
>> right now, but I don’t think this is the right way to go.
>>
>>> Considering the following enumeration:
>>>
>>> enum Bar {
>>> case foo(name: String)
>>> case notFoo
>>> case unknownFoo
>>> }
>>
>> One of the things we’ve discussed in the past is that we could have enums
>> automatically “synthesize” instance members for projecting cases as optional
>> values or bools. For example, the above enum could be compiled into the
>> equivalent of:
>>
>> extension Bar {
>> func getAsFoo() -> String? { … }
>> var isNotFoo : Bool { … }
>> var isUnknownFoo : Bool { … }
>> }
>>
>> Then you could just use:
>>
>> if someBar.isUnknownFoo { … }
>> if someBar.isFoo != nil { … }
>> if let name = someBar. getAsFoo() {... }
>> someBar. getAsFoo()?.doThing()
>>
>> etc. There is a question of naming, and getting the details right, of
>> course.
>>
>> -Chris
>> _______________________________________________
>> swift-evolution mailing list
>> [email protected] <mailto:[email protected]>
>> https://lists.swift.org/mailman/listinfo/swift-evolution
>
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