Algebraic Datatypes Puns

We know We have enum type and we never talk about Algebraic Datatype in Java? Why?

I love to see some examples from Haskell and Java to show why Algebraic Datatype so powerful In Haskell?

Or you can throw some Generic Algebraic Data Type examples, but I still struggling to understand what is GADT.

    public enum {
        Type1, Type2, Type3
    }



    -- Sum type
    data MyType a = Type1 a | Type2 a | Type3 a



    -- product type
    data CartesianProduct a = Product a a

For example,

data List a = Cons a (List a) | Nil
data Tree a = B (Tree a) a (Tree a) | Empty 

Correspond to lists and trees. Is there something analogous for sets? Or does that require more advanced types than Haskell supports?

Hello,

I am an undergraduate CS student planning on eventually pursuing a PhD (and hopefully career) in PL, more towards the theoretical end of the spectrum. I'm wondering what might be some good math classes to take. I'd assume that category theory, formal logic, and a models of computation course would be a good idea?

I am particularly interested in type theory and know that HoTT has roots in algebraic topology: would it be a good idea to try and take a class on that? If anyone has other suggestions that would be great.

I'm never sure what to search for when I'm looking for content on these things. Or even what to call them them I'm discussing online etc...

1. https://en.wikipedia.org/wiki/Tagged_union
2. https://en.wikipedia.org/wiki/Algebraic_data_type

I have a few questions related to this, I'll post them as separate comments below so that it makes it easier to reply to each separately.

For context of my background, I use these in TypeScript, and Rust (enums). And I've done some tinkering in Haskell. Those are the most-FP languages that I know. The only other languages I know are C# and PHP.

What to call these? Patterns like Ap themselves follow a meta-pattern which specifies applicative lifting where the operations all have the form opn = liftAn opn.. give or take lifting constants. Assume simplified classes and liftA0 = pure

instance (Applicative f, Semigroup a) => Semigroup (Ap f a) where
  (<>) = liftA2 (<>)
instance (Applicative f, Monoid a) => Monoid (Ap f a) where
  mempty = liftA0 mempty
instance (Applicative f, Bounded a) => Bounded (Ap f a) where
  minBound = liftA0 minBound
  maxBound = liftA0 maxBound
instance (Applicative f, Num a) => Num (Ap f a) where
  (+) = liftA2 (+)
  (-) = liftA2 (-)
  (*) = liftA2 (*)
  abs = liftA abs
  ..
  fromInteger = liftA0 . fromInteger

The pattern is somewhat simple but with no way to capture it, except by repeating it for every algebra. The instance head cannot be a type variable

instance (Applicative f, cls a) => cls (Ap f a) where
  ??

What would such a solution even look like? I don't want to get distracted by if the instance are all lawful, just capturing this meta-pattern the emerges.

• A generic representation for type classes to parallel Generic for datatypes.

• It can be implemented as a GHC plugin, like Evoke (blog, reddit, reddit)

• Or created on the fly by GHC, which is privy to the internal structure of type classes

    instance (Applicative f, cls a) => cls (Stocking1 Ap f a)

I don't want to step on anybody's toes here, but the amount of non-dad jokes here in this subreddit really annoys me. First of all, dad jokes CAN be NSFW, it clearly says so in the sub rules. Secondly, it doesn't automatically make it a dad joke if it's from a conversation between you and your child. Most importantly, the jokes that your CHILDREN tell YOU are not dad jokes. The point of a dad joke is that it's so cheesy only a dad who's trying to be funny would make such a joke. That's it. They are stupid plays on words, lame puns and so on. There has to be a clever pun or wordplay for it to be considered a dad joke.

Again, to all the fellow dads, I apologise if I'm sounding too harsh. But I just needed to get it off my chest.

Do your worst!

I'm surprised it hasn't decade.

For context I'm a Refuse Driver (Garbage man) & today I was on food waste. After I'd tipped I was checking the wagon for any defects when I spotted a lone pea balanced on the lifts.

I said "hey look, an escaPEA"

No one near me but it didn't half make me laugh for a good hour or so!

Edit: I can't believe how much this has blown up. Thank you everyone I've had a blast reading through the replies 😂

It really does, I swear!

Because she wanted to see the task manager.

They’re on standbi

Pilot on me!!

Nothing, he was gladiator.

Dad jokes are supposed to be jokes you can tell a kid and they will understand it and find it funny.

This sub is mostly just NSFW puns now.

If it needs a NSFW tag it's not a dad joke. There should just be a NSFW puns subreddit for that.

Edit* I'm not replying any longer and turning off notifications but to all those that say "no one cares", there sure are a lot of you arguing about it. Maybe I'm wrong but you people don't need to be rude about it. If you really don't care, don't comment.

When I got home, they were still there.

What did 0 say to 8 ?

" Nice Belt "

So What did 3 say to 8 ?

" Hey, you two stop making out "

I won't be doing that today!

[Removed]

Where ever you left it 🤷‍♀️🤭

This morning, my 4 year old daughter.

Daughter: I'm hungry

Me: nerves building, smile widening

Me: Hi hungry, I'm dad.

She had no idea what was going on but I finally did it.

Thank you all for listening.

There hasn't been a post all year!

You take away their little brooms