これでパターンマッチもできる Range になりました＼(^o^)／ #CodePiece

CodePiece.swift

struct MyForwardIndexTypeStruct {
    var num: Int
    init(_ num: Int) {
        self.num = num
    }
}

// Equatable
func == (lhs: MyForwardIndexTypeStruct, rhs: MyForwardIndexTypeStruct) -> Bool {
    return lhs.num == rhs.num
}

extension MyForwardIndexTypeStruct : ForwardIndexType {
    // _Incrementable
    func successor() -> MyForwardIndexTypeStruct {
        return MyForwardIndexTypeStruct(self.num+1)
    }
}

// --- 方法 1
// Swift 標準ライブラリにも幾つか定義されています。
//func ~=<I : ForwardIndexType where I : Comparable>(pattern: Range<I>, value: I) -> Bool
extension MyForwardIndexTypeStruct : Comparable {}
func <(lhs: MyForwardIndexTypeStruct, rhs: MyForwardIndexTypeStruct) -> Bool {
    print(__FUNCTION__)
    return lhs.num < rhs.num
}
func <=(lhs: MyForwardIndexTypeStruct, rhs: MyForwardIndexTypeStruct) -> Bool {
    print(__FUNCTION__)
    return lhs.num <= rhs.num
}
func >=(lhs: MyForwardIndexTypeStruct, rhs: MyForwardIndexTypeStruct) -> Bool {
    print(__FUNCTION__)
    return lhs.num >= rhs.num
}
func >(lhs: MyForwardIndexTypeStruct, rhs: MyForwardIndexTypeStruct) -> Bool {
    print(__FUNCTION__)
    return lhs.num > rhs.num
}

// --- 方法 2
// または自分で定義して使うこともできます。
func ~= (pattern: Range<MyForwardIndexTypeStruct>, value: MyForwardIndexTypeStruct) -> Bool {
    print(__FUNCTION__)
    return pattern.contains(value)
}

let start = MyForwardIndexTypeStruct(1)
let end = MyForwardIndexTypeStruct(5)
let myRange: Range = start ... end

print("start")
switch MyForwardIndexTypeStruct(2) {
case myRange:
    print("match")
default:
    print("")
}