[swift-evolution] [Pitch] Make `default` function parameter values more transparent

[Adrian Zubarev]

True but I think we should consider some consitency for apis, I'd prefer docs independent transparency but I could live with good documentation (guidline update?).

--  
Adrian Zubarev
Sent with Airmail  

Am 13. Juni 2016 um 06:27:22, Charlie Monroe (charlie at charliemonroe.net(mailto:charlie at charliemonroe.net)) schrieb:

>  
>  
> > On Jun 11, 2016, at 3:35 PM, Adrian Zubarev via swift-evolution <swift-evolution at swift.org(mailto:swift-evolution at swift.org)> wrote:  
> >  
> > I just installed the current Swift 3 snapshot to play around with it (last from may crashed my Xcode all the time).
> >  
> >  
> > I wanted to re-build a small project with (currently implemented) Swift 3 changes. Basically I had to look up on GitHub what the default value for deinitialize(count:) function was for UnsafeMutablePointer, just because Xcode and the docs can’t tell me that:
> >  
> > /// De-initialize the `count` `Pointee`s starting at `self`, returning /// their memory to an uninitialized state. /// /// - Precondition: The `Pointee`s at `self..<self + count` are /// initialized. /// /// - Postcondition: The memory is uninitialized. public func deinitialize(count: Int = default)  
> >  
> > To cut it short:
> >  
> > Could we make default function parameter values more transparent in Swift 3?
> > Why are default parameter values translated to default rather than the actual value?
> >  
> >  
> >  
>  
> I guess that in some cases you don't want the default value to be known, or is irrelevant. Most importantly, it can be a more complex expression - e.g. creating an object and calling something on it:
>  
> private let mySecretNumber = 0x999  
> public func deinitialize(count: Int = NSProcessInfo().processorCount + mySecretNumber)
>  
> And that's a pretty example, it can get much nastier. Since mySecretNumber is private, it definitely cannot be exposed.  
>  
>  
> > Can we make this independent from docs?  
> >  
> >  
> >  
> > --  
> > Adrian Zubarev
> > Sent with Airmail  
> >  
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> > swift-evolution at swift.org(mailto:swift-evolution at swift.org)
> > https://lists.swift.org/mailman/listinfo/swift-evolution
>  
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