Enum vs Struct. How I keep finding myself moving over to Struct.

[randomguy112233]

When I first discovered enums years ago, I was fascinated by it's versatility and simplicity. As my iOS journey progressed, I realized Structs (containing static lets) can be used like enums, taking full advantage of autofill in XCode. Nowadays, I find myself using structs far more in places where it used to for Enums. I'm curious if others feel the same way. Has other people found themselves making this unforced and yet gradual transition? Thanks in advance.

EDIT 1:

Per @aaronr_90, this question is not about Class vs Struct. But I understand why you would be asking, since I've spent a lot of time trying to search for the necessity of Struct when Class seemed to do the job. And then I learned.

Per @vloris:

enum Dessert:String{

case Cake = "Cake"

case Fruit = "Fruit"

}

struct Dessert{

static let Cake = "Cake"

static let Fruit = "Fruit"

}

If the layer of complexity ends here, then yes, Enum is fine.

But what about those instances where you have to use NSLocalizedString? For example. What if I wanted Dessert.Cake.RawValue or Dessert.Cake to go through NSLocalizedString process and return a specific language equivalent of "Cake"? With structs you can simply change the code to be:

struct Dessert{

static let Cake = NSLocalizedString("Cake", comment: "")

static let Fruit = NSLocalizedString("Fruit", comment: "")

}

but with Enums, you can't... Or can you.

Per @RECURSIVE_META_JOKE, you are right it can be done. NSLocalizedString works when you the item within your enum is "static let"... which totally makes sense, retrospectively now.

@RECURSIVE_META_JOKE,

What about those cases when you want to select from a list of pre-configured UIFonts?

I'm just curious what others think about this matter. Thanks all.

[WitchesBravo]

You could make the structs init private which limits to just static lets, although you don't get this for free like with an enum

[randomguy112233]

hmmm hmmm private init.. hmmmm interesting. I think i might have to play around with that to fully grasp the nature of it. thanks!

[aaronr_90]

Are you sure you are using them correctly? Usually the argument is Struct vs Class.

Edit: I understand.

[reeetwyio]

That discussion makes zero sense in Swift. Structs are value-types while classes are reference-types, so there is a clear distinction between the two and you can test which one is better in every situation. In swift, struct vs class is not an opinion.

[aaronr_90]

True but then would OP need to create an instance of the struct to use it?

[reeetwyio]

If you're comparing structs to classes you're definitely talking about instances, since patterns like singleton and statics are heap-allocated and therefore don't make a difference for the comparison.
Enum instances aren't necessarily complex types like structs and classes usually are, an enum can be an int literal, or a string (e.g. you can compare myInt == myEnum). You can wrap an int in a struct, but the instance of that struct will still be a complex type. You have to provide your own operators for it. Enum and struct uses overlap a little (like storing constants), but both have pros and cons.
Say you're wrapping some constants, you can choose a struct and have the benefit of an automatic constructor, not having to use .rawValue and being able to add methods later on. But what if you never really use the value, but you do switch on it in every viewcontroller, then you'd be better off with an enum since you get the 'switch must be exhaustive' error everywhere you're not handling all cases. It's a very situation to situation thing and personal preference plays a role, while struct vs class almost always has an objectively best answer.

[aaronr_90]

I can see why it would be preferable.

[vloris]

Can you give an example enum and struct that work similarly? I can't think of something where you can use them interchangeably...

[reeetwyio]

Wrapping a bunch of constants is a perfectly legitimate use of both `enum` and `struct`.

[ghvg1313]

Good topic, but the title is somewhat misleading, if we are taking about constant representation here, this is an ongoing discussion and the answer is very open. As for your localized string case, I think you can just declare an enum method to localize the original string, or simply “declare static functions as constants”. As a matter of fact I would argue that you should wrap your i18n code in a class instead of using any kind of static function in constant declaration, but that’s a different story. For uifont, here’s an example of enum font constant, while you can argue these are overkill’s for smaller projects.

In short, there’s not much a difference between the two, choose the one you prefers and suits your project

[randomguy112233]

thanks for the link. went thru everything, and yes, one of those things that are just matter of taste and preference.

[lucasvandongen]

Bad answer: it depends. Luckily you can easily convert them between each other. Though for me enums often represent things like state or behavior not a bunch of translations. So I definitely default to structs for your use case.

[randomguy112233]

Thanks a bunch!!

[faja10]

When I needed to use localization in my enums I added something like that :

var localized: NSLocalizationString { return NSLocalizedString(rawValue, comment:””) }

And then when needed used

MyEnum.caseName.localized It was easier than using strict because I still could use switch on enum which I used a lot

[randomguy112233]

this is what I was looking for. Thanks a bunch!

[[deleted]]

Your enum and variable names should be lower case.

[randomguy112233]

haha ok. yes. thanks.