🔰declaration

🚧 施工中

Swift ⟩ concept ⟩ declaration

defines new variables or types.

🔴 主題

• function

• class

• enum

• struct 🚧

• protocol

• ... 🚧

⭐️ 重點

use cases

• define functions and methods 🚧

• define variables and constants

• define enum, struct 🚧, class, protocol

• extend the behavior of an existing named type

• import symbols into your program that are declared elsewhere.

GRAMMAR OF A DECLARATION

• declaration → import-declaration

• declaration → constant-declaration

• declaration → variable-declaration

• declaration → typealias-declaration

• declaration → function-declaration

• declaration → enum-declaration

• declaration → struct-declaration

• declaration → class-declaration

• declaration → actor-declaration

• declaration → protocol-declaration

• declaration → initializer-declaration

• declaration → deinitializer-declaration

• declaration → extension-declaration

• declaration → subscript-declaration

• declaration → operator-declaration

• declaration → precedence-group-declaration

• declarations → declaration declarations opt

In Swift, most declarations are also definitions in the sense that they’re implemented or initialized at the same time they’re declared, .... the distinction isn’t that important in Swift, the term declaration covers both declarations and definitions.

👥 相關

• declaration is a simple statement.

📘 手冊

• Declarations