enum case pattern

Swift ⟩ Patterns ⟩

⭐️ 重點

Swift uses various overloads of the ~= operator to do pattern matching, which also lets us define our own overloads ... 👉 Sundell

💈範例

💾 程式：paiza.io

⬆️ 需要：CaseReflectable

// ------------
//     Enum
// ------------

// enum with associated values
// (conforms to `CaseReflectable`)
enum Enum: CaseReflectable {
    case int(Int)
    case int2(Int)
    case person(name: String, age: Int)
    case str(String)
}

// ------------
//     main
// ------------

let a: Enum = .int(3)

Enum.int ~= a        // true
Enum.int2 ~= a       // false

let joe = Enum.person(name: "joe", age: 8)

Enum.person ~= joe   // true
Enum.int ~= joe      // false

📗 參考

• Erica ⟩ Challenge: Filtering associated value enumeration arrays

• Austin Zheng ⟩ Custom pattern matching in Swift - custom array matching

• Ole ⟩ Pattern Matching in Swift - generic ~= operator

• Sundell ⟩

  • Five powerful, yet lesser-known ways to use Swift enums

    • Cases as Functions ⭐️

  • Pattern matching in Swift ⟩

    • Under the hood with custom matching - pattern match against any kind of Equatable Errors.

📘 手冊

• Swift Ref ⟩ Patterns ⟩ enum-case-pattern

• Swift Lib ⟩ Equatable ⟩ pattern-matching operator (~=)

🗣 討論

• How to filter array of enums with associated values?

• ~= operator in Swift ⭐️

• Comparing enum cases while ignoring associated values

👥 相關

• enum

• operator (~=)

• filter cases