[swift-evolution] Pitch: really_is and really_as operators

[Xiaodi Wu]

On Wed, Aug 24, 2016 at 9:47 PM, Xiaodi Wu <xiaodi.wu at gmail.com> wrote:

> Works on Linux :)
>

And besides, on any platform where `type(of: bar) != NSString`, why should
you expect `bar really_is NSString == true`? Isn't bar *not really*
NSString?

On Wed, Aug 24, 2016 at 9:44 PM, Charles Srstka <cocoadev at charlessoft.com>
> wrote:
>
>> On Aug 24, 2016, at 7:42 PM, Xiaodi Wu <xiaodi.wu at gmail.com> wrote:
>>
>>
>> import Foundation
>>
>> let foo: Any = "Hello"
>> type(of: foo) == String.self // true
>> type(of: foo) == NSString.self // false
>>
>> let bar: Any = "Hello" as NSString
>> type(of: bar) == String.self // false
>> type(of: bar) == NSString.self // true
>>
>> Why not this?
>>
>>
>> Because if you actually try that, it doesn’t work. type(of: bar) ==
>> NSString.self actually returns false, not true, because the actual instance
>> belongs to a private subclass of NSString, not NSString itself. type(of:
>> bar) == NSClassFromString(“__NSCFString”) works, but that doesn’t really
>> help us.
>>
>> Charles
>>
>
>
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