123日目

日記

冬が一番好き

今日書いたコード

struct SomeSpecialID: Equatable, ExpressibleByStringLiteral {
    let value: String

    init(stringLiteral value: String) {
        self.value = value
    }
}

enum Other: SomeSpecialID {
    case a, b, c
}
print(Other.a.rawValue)

感想

In particular, the raw-value type must conform to the Equatable protocol and one of the following protocols: ExpressibleByIntegerLiteral for integer literals, ExpressibleByFloatLiteral for floating-point literals, ExpressibleByStringLiteral for string literals that contain any number of characters, and ExpressibleByUnicodeScalarLiteral or ExpressibleByExtendedGraphemeClusterLiteral for string literals that contain only a single character.

https://docs.swift.org/swift-book/ReferenceManual/Declarations.html#grammar_union-style-enum-case