http://josephdepqbvoq7tm7uvynwmsji4354zmd3yp3rrtc245rilvq4ixayd.onion/posts/partial-in-swift
value ( for : key ) } set { values . updateValue ( newValue , forKey : key ) } } } Swift will pick the right one based on context. Downsides Using Partial does have some downsides. One is that you still have to create a custom init function, a requirement that could be removed by adding Partial to the standard library or made easier using metaprogramming tools such as Sourcery.