Custom subscripts were added to Objective-C in 2012. At that time, Chris Lattner was already two years into developing Swift, and like other good features, subscripts were added to the Swift language. I have not used custom subscripts in many other languages; however, I do find myself using subscripts extensively when I am developing in Swift. The syntax for using subscripts in Swift seems like a natural part of the language, possibly because they were part of the language when it was released and not added in later. Once you start using subscripts in Swift, you may find them indispensable.
In this chapter, you will learn the following topics:
- What custom subscripts are?
- How to add custom subscripts to classes, structures, ...