I have recently been digging into the API of Apple CryptoKit and were wondering about one design decision in particular: Why ist it that many of the types are modelled as enums instead of structs even if there are no cases defined (cf. eg. P256 and its nested types)? What are the benefits of this approach?
A case-less enum is Swift's closest approximation to a namespace.
The fact that case-less makes it impossible to accidentally instantiate.
6 Likes
Thanks, I suspected as much but was unsure if I was missing anything.
A struct, even one without properties, will receive a synthesized initializer, whereas an enum will not. This is why enums are used for namespaces.
1 Like