[swift-users] Bool to Int

[Rick Mann]

> 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