A common pattern when using closures in Swift is to add [weak self] in the captures list to hold a weak reference to self and avoid a retain cycle. This is then often followed by the following:

guard let self = self else { return }

But I often forget that capture lists can capture other variables in the current scope, so I thought I'd highlight some other use cases.

Today I have released the 1.0.0 version of a Swift package that aids with adding Equatable and Hashable conformance by using KeyPaths.

The package is available on GitHub.

I created the Swift Playground that sparked this concept in December 2018, so this concept has been rattling around in my brain for a couple of years. The API has changed a lot since the original concept, but the core has stayed the same: a protocol that requires a single function to be implemented that uses KeyPaths to synthesise Equatable and/or Hashable conformance.