Summary

In this chapter we provided an in-depth introduction to closures, which are self-contained blocks of code that can be passed around within our applications. We saw how closures can capture and retain references to variables or constants from the context in which they are created. Starting with simple examples, we learned how to define and execute closures, including ones that accept parameters and return values. We also touched on how closures can be used to increase code flexibility by passing them as function arguments and reusing them across different contexts, and we created a basic Logger type which demonstrated the power and flexibility of closures.

We also introduced Result Builders, a feature that allows us to create custom Domain-Specific Languages (DSLs) used for defining complex data structures. We saw how Result Builders, like closures, enhance code expressiveness and flexibility, making it easier to work with data structures such as JSON, HTML, and SwiftUI views....