We already saw Rust's if expressions, but those make decisions based on data values. Rust is a very type-conscious language, and so it's very important to be able to make decisions based on data types as well. Rust's match and if let expressions let us do that, comparing complex data types and allowing us to extract data values for further processing.

In this chapter, we're going to do the following:

• Learn how to use pattern matching in the context of variable assignment using the let statement
• Take what we've learned about pattern matching and apply it to decision making with the if let expression
• Use the match expression to choose exactly one of many possible patterns
• Use don't care values in pattern matching
• See how borrowing interacts with pattern matching
• Learn how to match complex, nested data structures