Can't mirrors solve this problem for Locale itself, instead of using NSLocale?
I do think that will affect performance though.
Rugen
> On 7 Sep 2016, at 09:03, Zhao Xin via swift-users <swift-users@swift.org>
> wrote:
>
> Now I understand your point. But as Jens said, Swift is a static language, it
> won't interpret `property` as a variable after `.`(dot). So for Swift
> compiler, you just refer to a none-exist property.
>
> Zhaoxin
>
>> On Wed, Sep 7, 2016 at 12:39 PM, Michael Sheaver <mshea...@me.com> wrote:
>> Hi Zhao,
>>
>> Many thanks for your response, and I will give this a try. However, I think
>> that I might have used a bad example for the bigger question I was trying to
>> ask, and for that I am sorry.
>>
>> The question that I am really trying to address here is: Is there a more
>> Swift-y way to, when passing a parameter to a function, we can tell it
>> whether:
>> a) we intend to pass in the literal string, or
>> b) we want to pass the contents of the named variable?
>>
>> I know that in some languages, if you prepend the passed parameter with a
>> '$', as in $propertyName, the receiving function knows to use the contents
>> of the variable named propertyName (in this case "calendar") instead of the
>> literal string "propertyName".
>>
>> Can we easily do this in Swift? If not, why not? Can we propose a change
>> request to implement either a computed property or a method on the Any()
>> class that would allow us to tell a called function whether we are passing
>> in a literal type or a variable that contains the data to be processed?
>>
>> Maybe this would violate the type safety for which Swift is thankfully so
>> strongly trying to preserve. I don't know, but I would at lest like to
>> consider it, for there ARE good business cases for it.
>>
>> Does this help to clarify the question. I am posing?
>>
>> Shawn, let me put this into a Swift file and shoot it your way.
>>
>> Many thanks!
>> Michael
>>
>>> On Sep 6, 2016, at 11:21 PM, Zhao Xin <owe...@gmail.com> wrote:
>>>
>>> I think you messed up with `Locale` and `NSLocale`.
>>>
>>> `Locale` is a struct in Swift 3 to replace the legacy `NSLocale`. The
>>> latter is a class, it has an inner `structure` called `NSLocale.Key`. For
>>> `Locale`, there is no `NSLocale.Key`. All there keys are instance
>>> properties in `Locale`. So in your specific case,
>>>
>>> let calendar2 = (currentLocale as
>>> NSLocale).object(forKey:NSLocale.Key(rawValue:propertyName))
>>>
>>> is just almost the same as `let calendar2 = calendar1`.
>>>
>>> If you insist on using `NSLocale.Key`, you should use `NSLocale` instead of
>>> `Locale`.
>>>
>>>
>>> Zhaoxin
>>>
>>>> On Wed, Sep 7, 2016 at 10:35 AM, Michael Sheaver via swift-users
>>>> <swift-users@swift.org> wrote:
>>>> I am trying to build a table of current locale properties in code, and
>>>> have encountered issues with trying to pass the value of a variable to a
>>>> function:
>>>>
>>>> let currentLocale = Locale(identifier: "en_US")
>>>>
>>>> let calendar1 = currentLocale.calendar // "gregorian (fixed)"
>>>>
>>>> let propertyName = "calendar"
>>>> let calendar2 = currentLocale.propertyName // Error: Value of type
>>>> 'Locale' has no member 'porpertyName'
>>>> In the last line of code above, the instance of Locale thinks I am passing
>>>> it "propertyName" rather than the contents of the variable "calendar".
>>>>
>>>> Is there any way to pass the value of propertyName ("calendar") to the
>>>> instance of Locale? I know that in other languages, you can prepend the
>>>> variable name like '$propertyName', and that tells it to read the value of
>>>> the variable.
>>>>
>>>> I want to keep this pure Swift if possible.
>>>>
>>>> I posted this question on StackOverflow, and got the following that does
>>>> work:
>>>>
>>>> let calendar2 =
>>>> (currentLocale as
>>>> NSLocale).object(forKey:NSLocale.Key(rawValue:propertyName))
>>>> It does seem odd to me that we must do some crazy Objective-C gymnastics
>>>> to make it work. It would seem logical to have a computed property on the
>>>> Any type named, let's say, contentsOf that would return or pass the
>>>> contents of the variable to the called function. For example, to use the
>>>> original code sample above, we could use:
>>>>
>>>> let calendar2 = currentLocale.propertyName.contentsOf
>>>>
>>>> or something similar. Thus currentLocale.propertyName would pass the
>>>> literal "propertyName", whereas currentLocale.propertyName.contentsOf
>>>> would pass the contents "calendar".
>>>>
>>>> Does anyone else agree that we need this functionality, or am I way out in
>>>> left field on this? Or is this already possible and I haven't yet figured
>>>> it out?
>>>>
>>>> Sincerest Regards,
>>>> Michael
>>>>
>>>> Michael Sheaver
>>>> mshea...@me.com
>>>>
>>>>
>>>> _______________________________________________
>>>> swift-users mailing list
>>>> swift-users@swift.org
>>>> https://lists.swift.org/mailman/listinfo/swift-users
>>>>
>>>
>>
>
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