As we saw in this chapter, adding support for subscripts to our custom types can greatly enhance their readability and usability. We saw that subscripts can be used to add an abstraction layer between our backend storage class and external code. Subscripts can also be used in a similar manner to computed properties, where the subscript is used to calculate a value. As we noted, the key with subscripts is to use them appropriately and in a manner that is consistent with subscripts in the Swift language.
In the next chapter, we will look at what closures are and how to use them.