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Comment by mseepgood | Hacker News Reader

Go doesn't have enums and as such they cannot suck. Something that is non-existent can't be good or bad. The title is clickbait. Go has constants, and they have a great feature for defining constants (iota).

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> Go has constants

That's literally what enums are: A set of named constants.

You might be thinking of what is traditionally known as sum types, which some people have recently started calling enums[1]. Indeed, Go does not have sum types.

[1] Presumably because of Rust using the wrong term when specifying its sum types

The article is about enums, which are lacking in Go.

No, Go definitely has enums. It is sum types (that some people have recently started calling enums) that Go lacks.

Go does not model enums as separate types (like e.g. Pascal), they are essentially just integers like C.

No, Go enums are definitely separate types. Sure, technically there is also an integer (or some other base representation) hidden in there somewhere, but that's what an enumeration is. Without that you don't have an enum.

Creating new types wrapping int is not really the same thing. It's not a closed set. Presumably one could define additional overlapping constants with the same integer type elsewhere?

Go types do not support value constraints, no. That has nothing to do with enums, though. That's a different feature altogether.

It has a lot to do with enums, especially if you are claiming statically typed enums. When defining a type, more often than not, we want to define the values that make up the set. For example, 'type boolean = true | false'

> we want to define the values that make up the set. For example, 'type boolean = true | false'

Sure, or, more relevant, `type monthOrdinal = 1-12` or `type email = {string}@{string}`. Any advanced type system will allow for that, of course, but Go does not. It does not even pretend to claim to be an advanced language. It has, quite explicitly, chosen to not be.

Yes, you are right that if Go had value constraints then an enum type could utilize those constraints, but, again, nothing to do with enums themselves. You are confusing unrelated features.

> You're confusing unrelated features

Actually I think you are. For example, almost all statically typed languages since Pascal do not have value constraints but support typed enums as closed sets. There's no advanced type system needed - no need to define enums as integers and then put additional constraints in the type system to try and restrict this. There is also no need to model enums as integers in the type system in order to use integers as a runtime representation.

You can't have closed enums without value constraints. Yes, some languages have been lazy and provided value constraints only for enum types.

Which is an interesting choice: Give a noose for developers to hang themselves with for every single other type other than enums – the types they are going to use most often – and not think twice, but then go full on helicopter parent when using enums – the one type that isn't particularly interesting.

It's a neat parlour trick, don't get me wrong, but I guess that's why almost all of the popular statically typed languages since Pascal (C, C++[1], Typescript[2], etc.) didn't bother with closed enums. They put their time into features that actually mattered to developers instead.

[1] Added later in life, granted.

[2] Ironically, does support value constraints except in the case of using enum.

> You can't have closed enums without value constraints

Sum types and closed enums don't need to constrain existing sets of values, they define the set of values. Again, I think you might be confusing the type system with runtime representation.

> It's a neat parlour trick, don't get me wrong,

It's a step towards sum types which are the mathematical dual of product types. Not a parlour trick at all, every modern language should have algebraic data types.

is there any further information on why Rust and other recent languages have started using `enum` to refer to sum types? I don't use Rust or TypeScript (edit: apparently TS doesn't have this, my memory is bad) or any of those languages and it's been very strange to see this redefinition occur

Typescript has actual enums. They behave just like Go's (for better or worse).

It's not clear why Rust got confused.

yep, sorry about that, I misremembered TypeScript as having the same "kind of enums" as Rust.

TypeScript has discriminated unions if that's what you were thinking of

https://www.typescriptlang.org/docs/handbook/2/narrowing.htm...

I think it might be due to the O'Caml influence on early Rust. They call them enums there[0].

[0] https://www.ocamlwiki.com/index.php?title=Enums_in_OCaml

They are called variants in OCaml (and inductive data types in Roqc).

But way more important: this OCaml wiki is an AI generated mess full of, well, bullshit. https://discuss.ocaml.org/t/whats-up-with-ocamlwiki/13605

Ah, I see. That's sad :(

... and now that you mention it, I do remember the variants terminology, esp. around the polymorphic variants feature. It's been 20+ years since I used OCaml, I'm afraid...

My best guess is Java.

Edit: I guess if you've never seen that this is, uh, controversial. Or something. Anyway, Java enums are full-strength classes, look at the planet example here https://docs.oracle.com/javase/tutorial/java/javaOO/enum.htm...

This is more like a Rust enum than a C one, I think you'll find.

Maybe to appeal to C and C++ developers. Rust makes its syntax superficially similar to C/C++ syntax in many other ways: pointer/reference syntax, declaration of "struct" types, generic types using <T>, curly brace block structure, and the naming conventions enforced by their lints. To be fair, many of these traits of C and C++ are also copied by other programming languages (e.g. curly braces). But they could have gone in a different direction and had pointer and record syntax more like Pascal, or made a syntax more like OCaml, Standard ML, or Haskell.

Using integers to model optional behaviour sucks, whatever you choose to call it. It's what one does in assembly language and C. Even Pascal from the early 70s had type-safe enumerations.

> The title is clickbait.

The article is an advertisement for the authors own Go package that addresses the "problem."

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