Modifierを簡単に定義する方法を考えたい

DynamicMemberModifier.swift

import Foundation

@dynamicMemberLookup
struct DynamicMemberWrap<T: AnyObject> {
    private var value: T

    init(_ value: T) {
        self.value = value
    }
    
    subscript<U>(dynamicMember keyPath: ReferenceWritableKeyPath<T, U>) -> (U) -> DynamicMemberWrap<T> {
        { val in
            value[keyPath: keyPath] = val
            return DynamicMemberWrap(value)
        }
    }

    subscript<U>(dynamicMember keyPath: ReferenceWritableKeyPath<T, U>) -> (U) -> T {
        { val in
            value[keyPath: keyPath] = val
            return value
        }
    }
}

postfix operator ^
postfix func ^<T: AnyObject>(lhs: T) -> DynamicMemberWrap<T> {
    return DynamicMemberWrap(lhs)
}

// Example:
//
//let label: UILabel = UILabel()^
//    .text("こんにちは\n88888")
//    .backgroundColor(.red)
//    .textColor(.green)
//    .shadowColor(.yellow)
//    .shadowOffset(.init(width: 3, height: 3))^
//    .alpha(0.5)
//    .numberOfLines(0)
//    .numberOfLines(1)
//    .numberOfLines(0)