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by bokwoon 2174 days ago
In Go you use the pattern of prefixing enum constants with the enum category to indicate that the enums are related to each other (e.g. StatusOk, StatusNotFound instead of status.OK, status.NotFound). Which is funny because today I came across this quote that "patterns are a demonstration of weakness in a language" in a Go talk https://youtu.be/5kj5ApnhPAE?t=276. I wish enums will eventually be implemented, generics are coming after all.
1 comments
H1Supreme 2174 days ago
I write Go nearly everyday, and enums are the #1 thing I'd like to see. Honestly, it's kind of surprising that the language lacks this feature.
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tleb_ 2174 days ago
See here for an explanation. Not sure it's up to date though. https://golang.org/doc/faq#variant_types
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tsimionescu 2174 days ago
Variant types are very different from enums. Variant types allow you to define a type that is "one of these N types". Enums are the same thing at the value level: they allow you to define a type that is "one of these values". You can't implement one in terms of the other.

Variant types do have some similar use cases with interfaces, but I don't see any relationship with enums in terms of use cases, so I don't think that applies.

Also, let's not forget that even C has enums, so their lack of inclusion in Go is baffling (especially since they went and implemented the much more arcane yet limited `iota` feature).

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masklinn 2174 days ago
> Also, let's not forget that even C has enums

Not in any useful sense of the word. A C enum is a typedef and a few named constant, it's absolute shit, and if the choice was restricted to "C enum or nothing" then "nothing" was absolutely the right call.

Go's typedecl + iota is actually a step up from C's enums, because (aside from "untyped constants") you need an explicit conversion from "any random integer" to your typedecl. It's not any more reliable or any safer at point of use, but it will prevent some misuses, or at least force the developer to consider what they're doing.

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cellularmitosis 2174 days ago
Yeah, I think the confusion stems from the word "enum" being used to mean different things in different langs.

A great illustration lies in comparing enums in Objective-C (essentially just named integers), whereas the associated values in Swift enums make them "Sum" types.

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