On 29.09.2017 3:56, Tony Allevato via swift-evolution wrote:
I don't want this to come across as though I'm trying to shut down discussion
(because it's not my place to do so), but a significant amount of time was spent
during the Swift 4 design phases debating how access levels should work, decisions
were made, and I think many of us would like to move on and give time to other topics.
I'd encourage you to look back through the archives and familiarize yourselves with
the points made during that time. While it's always possible, I think it's unlikely
that there will be new evidence introduced that would be so strong as to give the
Swift team reason to, once again, make major source-breaking changes to access levels
as late as Swift 5.
Tony, while I do understand and support your opinion and don't support the idea of
this pitch, don't you think we should fix the huge inconsistency with 'private
extension'?
private extension MyType {
/// This method have fileprivate access level, not private
func function() {...}
}
Such behavior had sense when extension was not able to keep private methods(who was
able to see them then), but currently it is perfectly OK to have extension with only
private methods in the same file with type.
And one can really use 'fileprivate extension' if this is an intention.
Existence of this inconsistency IMHO makes understanding of Swift access
modifiers/levels even harder(especially for newcomers), adds point of confusion and
even possible bugs(when code in same file accesses some method that really should be
private), and removes a very useful feature to move some private methods to extensions.
Thank you.
Vladimir.
On Thu, Sep 28, 2017 at 5:31 PM Jonathan Hull via swift-evolution
<swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote:
+1000
This is the way it always should have worked… and it is the way my brain
still
expects it to work. All of the extraneous “Public”s clutter the code and
make it
much more difficult to read. Without it, the relatively few properties
marked
Internal or Private stand out.
I know there is the argument about making people think about whether they
want to
expose each item… but it doesn’t work that way. Once you assign someone a
rote
task (assigning Public to most of the things), you lose the effect of
having them
think. From a cognitive psychology lens, when you give the brain a number
of
decisions to make in a row that are very similar, it will naturally make
that
task more efficient by automating as much of it as possible (i.e. thinking
about
it less). Mistakes become much more likely as a result.
Tl;dr: **Despite the*myth*/intention**that the current setup makes you*think
about the problem more,* it actually does the*opposite* and leads to an
*increased risk of error*.
Thanks,
Jon
On Sep 28, 2017, at 10:44 AM, James Valaitis via swift-evolution
<swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote:
When declaring a public class or struct the properties still default to
internal.
```
public final class NewType {
/// This property defaults to internal.
var property: Any?
}
```
This is not the same for a public extension on the type, where then the
access
modifier is respected for any function or calculated property within the
extension.
```
public extension NewType {
/// This function inherits the public modifier.
func function() {
}
}
```
I dislike this inconsistency, and I frequently find that when using my
dynamic
frameworks my code will not compile, and it will be due to my accidentally
writing a public struct but not declaring the properties public.
I believe in the idea that explicitly stating the access modifier leads to
more
legible code, but in my opinion it can be overdone, and I much prefer to
explicitly state my intentions in the modifier on the definition or
extension.
For example:
```
public struct Coordinate {
/// Should default to public.
let latitude: Double
/// Should default to public.
let longitude: Double
/// Should default to public
init?(latitude: Double, longitude: Double) {
guard validate(latitude: latitude, longitude: longitude) else { return nil }
…
}
}
internal extension Coordinate {
/// Convenience initialiser to me used internally within the module.
init(coordinate: CLLocationCoordinate2D) {
…
}
}
private extension Coordinate {
/// Private validation of the coordinate.
func validate(latitude: Double, longitude: Double) -> Bool {
…
}
}
```
This is legible and intuitive. The current behaviour is not.
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