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by ecedeno 164 days ago
Your example produces very distinguishable results. e.g. if Array.first finds a nil value it returns Optional<Type?>.some(.none), and if it doesn't find any value it returns Optional<Type?>.none

The two are not equal, and only the second one evaluates to true when compared to a naked nil.
1 comments
_flux 164 days ago
What language is this? I'd expect a language with a ? -type would not use an Optional type at all.

In languages such as OCaml, Haskell and Rust this of course works as you say.

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_rend 164 days ago
This is Swift, where Type? is syntax sugar for Optional<Type>. Swift's Optional is a standard sum type, with a lot of syntax sugar and compiler niceties to make common cases easier and nicer to work with.
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_flux 164 days ago
Right, so it's not like a union type Type | Null. Then naturally it works the same way as in the languages I listed.
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