Function Back Deployment
github.com
github.com
I never knew that was the intended use. I thought it was “available (to use) starting with (version)”
Edit: reading further, the example is backward from what I would have intuitively expected from the author’s arguments. So they’re advocating for using @available the way I thought it was used, and adding @backDeployed to indicate when it was added? I find this confusion and unnecessary.
@available is, indeed, when something was actually introduced. As you put it, "available to use starting with this version."
@backDeployed is for when something could've worked on an earlier version, if you just copied and pasted the function body. So something that has relatively straightforward logic, doesn't change the layout of or introduce new structs, etc.
Then when you build the project, the compiler can figure out if it can just use the library's version of the function (target >= @available) or if it needs to copy over the definition itself (@backDeployed <= target < @available). But from your perspective as a consumer of the function, you can act like it's been present since the version indicated in @backDeployed.
extension Toaster {
@available(toasterOS 1.0, *)
@backDeployed(before: toasterOS 2.0)
public func makeBatchOfToast(_ breadSlices: [BreadSlice]) -> [Toast] { ... }
}
I would have expected `@available(toasterOS 2.0, *)` indicating this was not implemented until 2.0, followed by `@backDeployed(toasterOS 1.0` indicating it's also available to this earlier version.
Please correct me where I've gone wayward.
My proposal would be `@available(toasterOS VersionOlderThanCurrent)` indicating this is available for use in that older version, and an optional `@developedWith(toasterOS CurrentVersion)`
Edit: you say
> @available is, indeed, when something was actually introduced. As you put it, "available to use starting with this version."
Let me be clear in my intent: I read the linked article as saying @available is "I implemented this using version X", and I always thought it was "this will [only] work on version X (or later?)" regardless of when it was actually written. These have different meanings - that is my intent.
If this means Apple is more likely to let me use SwiftUI iOS 17 features when targeting iOS 16 devices, it’s pretty exciting.