UpperCamelCase has been replaced with lowerCamelCase for enums and properties
UpperCamelCase has been replaced with lowerCamelCase for enums and properties 관련
Available from Swift 3.0
Although syntactically irrelevant, the capital letters we use to name classes and structs, properties, enums, and more have always followed a convention fairly closely: classes, structs, and enums use UpperCamelCase (MyStruct, WeatherType.Cloudy), properties and parameter names use lowerCamelCase (emailAddress, requestString).
I say "fairly closely" because there are some exceptions that are going to stop being exceptions in Swift 3: properties and parameters that started with initials in Swift 2.2 will now used lowerCamelCase in Swift 3.
Sometimes this isn't too strange: Swift 2.2 created NSURLRequest objects using NSURLRequest(URL: someURL) – note the capital "URL". Swift 3 rewrites that to URLRequest(url: someURL), and also means you'll use things like webView.request?.url?.absoluteString for reading the URL of a web view.
Where it's a bit more jarring is when only part of the property name is in caps, e.g. CGColor or CIColor. Yes, you've guessed it: they become cgColor and ciColor in Swift 3, so you'll be writing code like this:
let red = UIColor.red.cgColor
This change does help drive consistency: all properties and parameters should start with a lowercase letter, no exceptions.
At the same time enum cases are also changing, moving from UpperCamelCase to lowerCamelCase. This makes sense: an enum is a data type (like a struct), but enum values are closer to properties. However, it does mean that wherever you've used an Apple enum, it will now be lowercase. So:
UIInterfaceOrientationMask.Portrait // old
UIInterfaceOrientationMask.portrait // new
NSTextAlignment.Left // old
NSTextAlignment.left // new
SKBlendMode.Replace // old
SKBlendMode.replace // new
You get the idea. However, this tiny change brings something much bigger because Swift's optionals are actually just an enum under the hood, like this:
enum Optional {
case None
case Some(Wrapped)
}
This means if you use .Some to work with optionals, you'll need to switch to .some instead. Of course, you could always take this opportunity to ditch .some entirely – these two pieces of code are identical:
for case let .some(datum) in data {
print(datum)
}
for case let datum? in data {
print(datum)
}
Changes in Swift 3.0