null / nil in swift language

Question

How would we define the following in swift programming language :

• null
• nil
• Nil
• [NSNull null]

In other words, what would be the swift equivalent of each of these objective c terms. Besides, would also like to know whether any specific use cases exist for non objective c types like structs and enums. Thanks in advance.

Answer 1

Regarding equivalents:

• NULL has no equivalent in Swift.
• nil is also called nil in Swift
• Nil has no equivalent in Swift
• [NSNull null] can be accessed in Swift as NSNull()

Note: These are my guesses based on reading and play. Corrections welcome.

But nil/NULL handling in Swift is very different from Objective C. It looks designed to enforce safety and care. Read up on optionals in the manual. Generally speaking a variable can't be NULL at all and when you need to represent the "absence of a value" you do so declaratively.