[swift-evolution] [Pitch] UnsafePointer.advanced(to:)
dabrahams at apple.com
Tue Jun 6 14:56:48 CDT 2017
on Tue Jun 06 2017, Brent Royal-Gordon <swift-evolution at swift.org> wrote:
>> On Jun 6, 2017, at 9:06 AM, Xiaodi Wu <xiaodi.wu at gmail.com> wrote:
>> Why would this be an extension on UnsafePointer and not KeyPath?
> 1. I can't come up with a name as good as `advanced(to:)` that would
> be attached to the key path. I use `advance(_:)` in the other two
> reasons below, but I don't think it's nearly as clear about what it's
> doing to the pointer.
> 2. Passing the pointer as the parameter would encourage use of `&`, which would be invalid.
> (\CGRect.origin.y).advance(&myRect) // Pointer might be to a temporary
> (&myRect).advanced(to: \.origin.y) // Rejected during compilation because & is not allowed
> 3. Passing the key path as a parameter improves the code's appearance when you specify the key path
> in the expression.
> myRectPtr.advanced(to: \.origin.y)
> (\CGRect.origin.y).advance(myRectPtr) // Requires explicit type name and extra parentheses
IIUC this has nothing to do with "advancing", though. Maybe "applying"
or even "map" would be a better name?
More information about the swift-evolution