Original "description" of CustomStringConvertible type

Using Swift
2

Hmm… you're maybe looking for something like this?

Which maybe needs something like this?

This seems to be producing the correct output:

//  https://github.com/swiftlang/swift/blob/main/docs/StandardLibraryProgrammersManual.md#_silgen_name

@_silgen_name("swift_EnumCaseName")
internal func _getEnumCaseName<T>(_ value: T) -> UnsafePointer<CChar>?

enum E: CustomStringConvertible {
  case payloadless
  case withPayload(String)
  case withPayloadAndLabel(label: String)
  case withPayloadAndEmptyLabel(_ label: String)
  case withPayloadAndTwoLabels(_ label: String, _ other: Int)
  
  var description: String {
    "Something + " + originalDescription(self)
  }
}

func originalDescription(_ value: Any) -> String {
  let mirror = Mirror(reflecting: value)
  return switch mirror.displayStyle {
  case .enum:
    if let first = mirror.children.first {
      if let label = first.label {
        "\(label) \(first.value)"
      } else {
        "what do I do?"
      }
    } else {
      if let cString = _getEnumCaseName(value),
         let caseName = String(validatingCString: cString) {
        caseName
      } else {
        fatalError("usupported yet")
      }
    }
  default:
    fatalError("usupported yet")
  }
}

print(E.payloadless)

Whether or not you want to ship this _silgen_name solution in your production app is another question.

The docs say that shims should be preferred over _silgen_name… but the documentation for shims is a TODO:

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