VermeerByte's Blog

Ⅰ.IntroductionHave you ever encountered a situation where your function’s parameters — especially closure parameters — become overwhelmingly long and cluttered? For example: 123func handle(success: ((Int) -> Int)?, failure: ((Error) -> Void)?, progress: ((Double) -> Void)?) { } We can use typealias to helps you simplify complex types. Like this: 12345typealias Success = (Int) -> Inttypealias Failure = (Error) -> Voidtypealias Progress = (Double) ...

Ⅰ.What is () -> Void in Swift?It represents a closure that takes no parameters and returns no value.Let’s break it down: Part Meaning () No input parameters -> Indicates a return type Void No return value (Void means nothing) Ⅱ.In plain language:() -> Void means: “A block of code that takes nothing in, returns nothing out — it just runs.” Example:12345let sayHello: () -> Void = { print("Hello!")}sayHello() // Output: Hello! This sayHello is a c...

Trailing Closures in SwiftⅠ.IntroductionTrailing closures are one of Swift’s most distinctive and frequently used features, especially in asynchronous callbacks, animations, and data processing. Let’s dive deep into this essential concept. Ⅱ.What is a Trailing Closure?A Trailing Closure is a special syntax in Swift where,if the final parameter of a function is a closure, you can write that closure outside the parentheses of the function call. This makes your code cleaner and more readable. A...

Functions as First-Class CitizensI. What Are “First-Class Citizens”?First-Class Citizens refer to entities (typically data types) in a programming language that can be used like variables. They must satisfy three key characteristics: Characteristic Meaning Assignable Can be assigned to variables or constants Passable as parameters Can be passed as arguments to other functions Returnable Can be returned from other functions In Swift, functions are first-class citizens! II. Demon...

Swift ClosuresI. DefinitionClosures in Swift are defined as self-contained blocks of executable code that can capture variables or constants from their context. This means they can “remember” the environment in which they were created, even after that environment no longer exists. A common way to think of closures is as “nameless functions“though this is a simplification. II. FormsIn Swift, functions are technically a form of closure, leading to the following insights: All functions are closu...