scaffold_extension.swift

extension ArgumentSet {
  init(_ type: ParsableArguments.Type) {
    let a: [ArgumentSet] = Mirror(reflecting: type.init())
      .children
      .compactMap { child in
        guard
          var codingKey = child.label,
          let parsed = child.value as? ArgumentSetProvider
          else { return nil }

        // Property wrappers have underscore-prefixed names
        codingKey = String(codingKey.first == "_" ? codingKey.dropFirst(1) : codingKey.dropFirst(0))

        let key = InputKey(rawValue: codingKey)
        return parsed.argumentSet(for: key)
    }
    self.init(additive: a)
  }
}