[swift-users] Bool to Int

[Adrian Zubarev]

Where is your problem here? It’s simple and easy ;)

extension Integer {
     
    init(_ boolean: Bool) {
         
        self = boolean ? 1 : 0
    }
}


Int(10 > 4)
UInt32(1 <= 2)


-- 
Adrian Zubarev
Sent with Airmail

Am 22. November 2016 um 00:54:47, Rick Mann via swift-users (swift-users at swift.org) schrieb:


> On Nov 21, 2016, at 15:09 , Marco S Hyman <marc at snafu.org> wrote:
>  
>> Except it does, because if I write
>>  
>> let a = 2
>  
>> a is of type Int (at least, according to Xcode's code completion).
>  
> and if you write
>  
> let b = 2 + 0.5
>  
> 2 is treated as a double. The type of the literal “2” varies with context. Do you also find that inconsistent and confusing?  

Nope. I can see how the promotion works. Also, Xcode would tell me b is a Double.

>  
>> But this gives inconsistent results:
>>  
>> let t = true
>>  
>> let a = Int(true)
>> let b = Int(t)	// Error
>>  
>> I find this to be very inconsistent and confusing.
>  
> t is a Bool and there is no automatic conversion from Bool to Int.
>  
> true is not a Bool. It may be treated as a Bool depending upon context. In the line `let t = true` it is treated as a Bool. In `let a = Int(true)` it is treated as an NSNumber (assuming you import foundation).

That may be what's happening, but it's still confusing and unintuitive. That something is lost in the transitivity of going through a variable, aside from "literalness", is confusing.  

And really, it would be nice if the language provided a fast way of getting an number "1" out of a Bool variable true (and 0 out of false). But that conversation is a bigger can of worms than I care to open right now.

--  
Rick Mann
rmann at latencyzero.com


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