What is frozen struct in Swift?
frozen. Apply this attribute to a structure or enumeration declaration to restrict the kinds of changes you can make to the type. This attribute is allowed only when compiling in library evolution mode.
What is an attribute in Swift?
Attributes provide more information about a declaration or type. There are two kinds of attributes in Swift, those that apply to declarations and those that apply to types.
What is Ns_closed_enum?
When you use NS_CLOSED_ENUM , you are making a promise to consumers of your API that the enum will never change, either now in the future. Of course, there is nothing stopping you from making that change, but if you do, you’ve now broken that promise. As you said, it compiles fine after updating the switch cases.
Why do we use enum in Swift?
An enumeration defines a common type for a group of related values and enables you to work with those values in a type-safe way within your code. Enumerations in Swift are much more flexible, and don’t have to provide a value for each case of the enumeration.
What does @objc mean in Swift?
@objc means you want your Swift code (class, method, property, etc.) to be visible from Objective-C. dynamic means you want to use Objective-C dynamic dispatch.
What is @available in Swift?
@available. In Swift, you use the @available attribute to annotate APIs with availability information, such as “this API is deprecated in macOS 10.15” or “this API requires Swift 5.1 or higher”.
What is mirror in Swift?
Overview. A mirror describes the parts that make up a particular instance, such as the instance’s stored properties, collection or tuple elements, or its active enumeration case. Mirrors also provide a “display style” property that suggests how this mirror might be rendered.
What is a Keypath in Swift?
Swift keypaths are a way of storing uninvoked references to properties, which is a fancy way of saying they refer to a property itself rather than to that property’s value.
What is Inlinable in Swift?
Introduced in Swift 4.2, the @inlinable attribute allows you to enable cross-module inlining for a particular method. When this is done, the implementation of the method will be exposed as part of the module’s public interface, allowing the compiler to further optimize calls made from different modules.
What is Objective-C used for?
Objective-C is the primary programming language you use when writing software for OS X and iOS. It’s a superset of the C programming language and provides object-oriented capabilities and a dynamic runtime.
What is lazy keyword in Swift?
A lazy var is a property whose initial value is not calculated until the first time it’s called. A lazy stored property is a property whose initial value is not calculated until the first time it is used. You indicate a lazy stored property by writing the lazy modifier before its declaration.
What is closure in Swift?
Closures are self-contained blocks of functionality that can be passed around and used in your code. Closures in Swift are similar to blocks in C and Objective-C and to lambdas in other programming languages. Nested functions are closures that have a name and can capture values from their enclosing function. …
What is a frozen enum in Swift?
The change also adds the concept of a frozen enum which is not intended to get any new cases. It only applies to C, or Objective-C, enums imported to Swift. One example from the standard library is ComparisonResult. This is the Objective-C definition: There are only three possible results for comparison so this enum should never change.
How to enable library Evolution in Swift for frozen structures?
The properties of a frozen structure can’t have property observers, and expressions that provide the initial value for stored instance properties must follow the same restrictions as inlinable functions, as discussed in inlinable. To enable library evolution mode on the command line, pass the -enable-library-evolution option to the Swift compiler.
What does unavailable and introduced mean in Swift?
The unavailable argument indicates that the declaration isn’t available on the specified platform. This argument can’t be used when specifying Swift version availability. The introduced argument indicates the first version of the specified platform or language in which the declaration was introduced.
How does the remainder operator ( (\%) work in Swift?
The remainder operator (\%) is also known as a modulo operator in other languages. However, its behavior in Swift for negative numbers means that, strictly speaking, it’s a remainder rather than a modulo operation. Here’s how the remainder operator works. To calculate 9 \% 4, you first work out how many 4 s will fit inside 9:
https://www.youtube.com/watch?v=8_Xmod1C2ww