Hands-On Design Patterns with Swift

Contributors, thank you notes, and the visitor pattern

We'll now put those protocols to work. Let's imagine you're building an app that helps open source maintainers. New contributors are rare, and it's important to thank them in a timely manner.

Let's implement a simple program that will determine who to send a thank you note to, 3 days after their contribution, out of all the contributions to the repository:

struct Contribution {    let date: Date    let author: String    let email: String    let details: String}

Contribution is a simple object of itself, which holds information about the contributor and their contribution.

Now we need to make those Contribution objects Visitable so we can use Visitors on them:

extension Contribution: Visitable {} ...