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swift difference between final var and non-final var | final let and non-final let
(2 answers)
What is the difference between final Class and Class?
(7 answers)
Closed 3 years ago.
A newbie question.
I'm reading swift documentation AccessControl. It says there are 5 access specifiers.
Open
Public
Internal
File-private
Private
I thought Final is also an access specifier. If not what is it? And can someone give link to the documentation?
It's not an Access Control Specifier, it's a Declaration Modifier.
final
Apply this modifier to a class or to a property, method, or subscript member of a class. It’s applied to a class to indicate that the class can’t be subclassed. It’s applied to a property, method, or subscript of a class to indicate that a class member can’t be overridden in any subclass.
Source: Swift Language Reference - Declaration – Declaration Modifiers
Related
This question already has answers here:
Calling a Swift class factory method with leading dot notation?
(3 answers)
Closed 5 years ago.
I am currently coding my own app and I was looking at a coding video for help and the person in the video was using .text and some other things that had dots in front of them like .color and .shape, which were variables declared and initialized already. I was wondering if anybody has a clear definition on what the .text means or what it does and what the overall dot means whenever you use it.
This feature is called "Implicit Member Expression"
An implicit member expression is an abbreviated way to access a member of a type, such as an enumeration case or a class method, in a context where type inference can determine the implied type. It has the following form:
.member name
For example : if you want to pick a color, in Swift4 you can simply do so:
let color: UIColor = .green
instead of typing :
let color : UIColor = UIColor.green()
This question already has answers here:
Swift protocol error: 'weak' cannot be applied to non-class type
(5 answers)
What exactly does `: class` do in a protocol declaration?
(1 answer)
Swift: how to work around issue where weak variable of type 'protocol' is illegal
(1 answer)
Closed 5 years ago.
Since I don't know what the name is for the following thing, I don't know how to use proper words to describe my question. ANyway, I am wondering what is the :class ? What does it mean? and what does it do?
protocol MyDelegate: class {
func doTask()
}
==== update ===
OK, I got the answer, thanks guys, but it would be nice not only tell it is class-only protocol. But also what about enum & struct only protocol, because naturally this question will raise up, is there a way to define enum-only and struct-only protocol then?
class in your case means that classes only can implement your protocol and not structs.
That means that only classes (not structs) can implement it.
It means that you can conform to this protocol only classes, not structures or enums.
This question already has answers here:
Difference between static function and singleton class in swift [closed]
(3 answers)
Closed 6 years ago.
I have made a class that will contain all the utility methods. So, instead of making it as a singleton, I have marked the methods as static and accessing those methods by the ClassName.methodName without the need for instantiation.
Is this approach OK?
Just consider that a singleton is used in order to ensure that only one instance exists for a given class, and that there’s a global access point to that instance.
I believe that having all utility functions marked as static within a class is a good approach since, as you have stated, you will need to use ClassName.methodName in order to use them.
In addition, based on what you want to achieve and the information provided by this link, I would reassert that having a class with static methods is the best alternative.
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What is a good example to differentiate between fileprivate and private in Swift3
(10 answers)
Closed 6 years ago.
I'm starting in swift and opening a project created using swift2 from xcode 8 beta, the private modifier were changed to fileprivate. what does this keyword means? and how is different from private ?
fileprivate is one of the new Swift 3 access modifiers that replaces private in its meaning. fileprivate defines an entity (class, extension, property, ...) as private to everybody outside the source file it is declared in, but accessible to all entities in that source file.
private restricts the entity in the direct enclosing scope.
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What is the rationale behind having companion objects in Scala?
(7 answers)
Closed 7 years ago.
As we know we don't have static methods in scala. If we have to achieve that taste we declare that class as object. But the problem is that when we declare class as object then all methods present in that object becomes static. And in class all methods all non-static. What I want is that to have static as well as non static methods in the same class, Is it possible? Definitely it would be possible but how??????
To do what you are trying do in Scala you create an object and a class of same name. Put static in object and instance members in Class version of it. This object is called a companion object.