Protocol Custom​Dump​String​Convertible

public protocol CustomDumpStringConvertible  

Types that want to customize their dump output can conform to this protocol. It is most appropriate for types that have a simple, un-nested internal representation, and typically its output fits on a single line, for example dates, UUIDs, URLs, etc.

For data types with more structure, for example those with nesting and multiple fields, see the CustomDumpReflectable protocol.

The library conforms a bunch of Foundation types to this protocol to simplify their dump output:

extension URL: CustomDumpStringConvertible {
  public var customDumpDescription: String {
    "URL(\(self.absoluteString))"
  }
}

customDump(URL(string: "https://www.pointfree.co/")!)

URL(https://www.pointfree.co/)

Custom Dump also uses this protocol internally to provide more useful output for enums imported from Objective-C:

import UserNotifications

print("dump:")
dump(UNNotificationSetting.disabled)
print("customDump:")
customDump(UNNotificationSetting.disabled)

dump:
- __C.UNNotificationSetting
customDump:
UNNotificationSettings.disabled

Any time you want to override the dump representation with some other string, you can use this protocol.

For example, you could introduce a wrapper type that "redacts" a portion of a dump:

struct Redacted<RawValue>: CustomDumpStringConvertible {
  let rawValue: RawValue

  var customDumpDescription: String {
    "<redacted>"
  }
}

customDump(Redacted(rawValue: "my super secret password"))

<redacted>

var customDumpDescription: String