Difference between Printable and DebugPrintable in Swift

Question

Looking for a Swift equivalent of Cocoa's description, I found the following protocols in Swift: Printable and DebugPrintable.

What's the difference between these two protocols and when should I use each one?

Answer 1

Here is an example class

class Foo: Printable, DebugPrintable {
    var description: String {
        return "Foo"
    }
    var debugDescription: String {
        return "debug Foo"
    }
}

This is how to use it.

println(Foo())
debugPrintln(Foo())

Here is the output with no surprises:

Foo
debug Foo

I didn't try this in a Playground. It works in an actual project.

The answer above was for Swift 1. It was correct at the time.

Update for Swift 2.

println and debugPrintln are gone and the protocols have been renamed.

class Foo: CustomStringConvertible, CustomDebugStringConvertible {
    var description: String {
        return "Foo"
    }
    var debugDescription: String {
        return "debug Foo"
    }
}

print(Foo())
debugPrint(Foo())