Custom Types

Rust provides two options for creating custom types: enum and struct. The key difference between them is that enums have a fixed set of variants, meaning they are used to indicate that a value is one of a specific set of possible values. On the other hand, struct is not limited to a set of possible values. Structures allow for packaging related values into meaningful groups.

We've already encountered enums when we looked at Option and Result.

In our current rustle program, we use tuples to represent intervals. In this section, we'll replace tuples with a custom Interval type using a struct, and enhance it by adding methods for various operations. Finally, we'll define an enum to represent potential error values when creating and interacting with intervals.