I think people mean different things by enums. Is it just a set of constants of a given type or a sum type (aka variant type)?
Go doesn't have sum types at all.
`iota` is just a syntax sugar for enumerating integer constants/variables.
But as you're talking about string enums, the Go equivalent would be:
type Season string
const (
Summer Season = "Summer"
Autumn = "Autumn"
Winter = "Winter"
Spring = "Spring"
)
But, again, that's not a variant type, so you can still assign a different value to the variable of the type Season. Which is rarely a problem in practice (there are other ways to validate data rather than by type system constraints).
So just to clarify, many of the use cases for enumerated values do not need string representation. Go has no magical way to translate varibale/const name into the string.
> An enum type is a special data type that enables for a variable to be a set of predefined constants. The variable must be equal to one of the values that have been predefined for it. [0]
> Is it just a set of constants of a given type or a sum type (aka variant type)?
So by above definition, it is a set of predefined constants.
> But, again, that's not a variant type, so you can still assign a different value to the variable of the type Season.
Which kinda defeats the purpose doesn't it?
> Which is rarely a problem in practice (there are other ways to validate data rather than by type system constraints).
I'm not sure I agree that it is a rare problem - if I can't rely on the type system to do a check that something belongs to a set of predefined constants, that is a pretty basic part missing. Of course there would be other ways but being able to lean on the type system would be a pretty reasonable expectation.
> So just to clarify, many of the use cases for enumerated values do not need string representation.
Sure - just like many of the use cases do require string representation. It is not unreasonable to expect that enumerations as defined above should be able handle cases that do and don't require string representation.
> Go has no magical way to translate varibale/const name into the string.
You keep using this word magical when it comes to addressing the limitations of the language. Java isn't doing "magic" when it is able to return a string representation of the enum value - it is part of the language. Credit where credit is due etc.
Have you actually tried it or you just ranting that Go is not Java?
Take `time.Weekday` type, for example from Go stdlib. It's a typical use of kinda enums in Go. [1]
It serves the purpose to effectively use Weekday whenever it's needed – in literals, in tests, in debug output, etc. Internally it's just an int, but for humans it's better to work with named predefined constants. Instead of creating yet another language feature that will automagically (yes, I keep repeating it, because it matters) convert variable names into strings, Weekday type leverages other Go features to achieve it in a more appropriate way, implementing proper string conversion for long and short forms for English and leaving room for proper i18n handling (it's still a named int constant). [2] Having it as a separate named type makes it handy for proper type checking (so you can't pass some integer with incorrect value to the function expecting time.Weekday).
And now you're saying that it's all useless and wrong, because compiler is not enforcing range of values that varaible of this type can have. But I tell you that it's useful and helping code readability enormously even without being a sum type.
And I hope it's clear that when you switch to another language, the worst thing you can do is to complain that it's different from your previous favourite language. You not just switching use another syntax, but you changing the ways to do things and even philosophy. It's like moving to another country - you not just changing a language, you switching to a different culture and economy. You adopt their social norms, follow the rules of that country and pay taxes even if in your country it was all different.
So yeah, in Go there are no sum types aka enums. And you know what, Go is extremely effective at what it was designed to despite of this. And "Go enums" work just fine, until they may be improved in the future when community is in consensus on how implement it, respecting backward-compatibility rule.
Go doesn't have sum types at all.
`iota` is just a syntax sugar for enumerating integer constants/variables.
But as you're talking about string enums, the Go equivalent would be:
But, again, that's not a variant type, so you can still assign a different value to the variable of the type Season. Which is rarely a problem in practice (there are other ways to validate data rather than by type system constraints).So just to clarify, many of the use cases for enumerated values do not need string representation. Go has no magical way to translate varibale/const name into the string.