Yet another Hacker News

22 points Thom2503 3 days ago 15 comments

adamddev1 1 hour ago | parent

The more of Haskell's ideas that bleed into mainstream languages, the happier the world will become. It is just so beautiful how these higher abstractions can become so useful and powerful for tying all kinds of things together.

thomasfromcdnjs 1 hour ago | parent

I've been vibe coding my own language and it's compiler is in Haskell, it's been great for the agents to be inspired by Haskell and I'm having fun just adding random language features, currently implementing prophecy ghost variables. Not really a public project but can suss it out for now at http://lsalpha.com

bigmadshoe 45 minutes ago | parent

This is super cool! You should put a clear example implementation of a feed forward network, transformer block, loss function, or something more ML specific on the homepage, assuming you're primarily targeting that domain.

EDIT: also the links to GitHub on https://lsalpha.com/systems are 404ing for me, so I exited your site without an example of what a real implementation might look like.

i2talics 1 hour ago | parent

I've long suspected that one of the things that makes monads notoriously difficult to explain to people outside of the Haskell ecosystem is that very few other languages even have a kind system that you are allowed to manipulate in code (and in some, like C++, it's so esoteric that you basically never see it). First explaining that you can even abstract over "type->type" kinded things gets you a lot of the way towards monads without actually describing monads.

caaqil 42 minutes ago | parent

> things that makes monads notoriously difficult to explain to people outside of the Haskell ecosystem

Huh, I thought a monad is just a monoid in the category of endofunctors, what's the problem?

girvo 38 minutes ago | parent

And here I was convinced that they’re burritos!

I will say that explaining functors to my coworkers was always much simpler, and then naturally led to monads

epolanski 33 minutes ago | parent

The thing that makes monads difficult is laziness and the anti math circle jerk.

You start from a functor which is a data type that admits a map operation.

Then you add of, or pure, to make an applicative functor, and then you add flatmap to make a monad.

LoganDark 30 minutes ago | parent

> The thing that makes monads difficult is laziness and the anti math circle jerk.

That's quite a hateful way to describe lack of knowledge.

There are some prerequisites that make it easier to understand monads, and a lot of programmers don't even know those. That can make learning monads difficult right off the bat.

epolanski 15 minutes ago | parent

No there's no complexity behind monads except laziness and anti math circle jerk.

It's really basic concepts, much easier than the analysis you do in high school.

But people would rather sit through monad as boxes or burritos cringe tutorials.

xboxnolifes 9 minutes ago | parent

Your math explanation starts with a math concept that the vast, vast, vast majority of people will have never even heard of, even in math-adjacent fields. It's not anti-math reasoning. It's a lack of self-awareness that your background is very math heavy, which makes that particular explanation make sense to you. I've gone my entire schooling, as a student who was always one of the few who were "good at math", all the the way through my CS education, without ever having heard of a functor until I came across the Haskell monad explanation meme.

Your next step could be to blame the school systems if you want, but that doesn't help the situation at hand.

taolson 16 minutes ago | parent

That may be true for functions which operate on a generic Monad typeclass, but typeclasses (Higher kinded types) aren't required to implement concrete Functor / Applicative / Monad instances for a particular type, e.g. Maybe:

    fmap f Nothing = Nothing
    fmap f (Just x) = Just (f x)

    pure x = Just x

    Nothing >>= f = Nothing
    Just x >>= f = f x

rramadass 7 minutes ago | parent

Some OO languages have a parallel concept in "Metaclass" (https://en.wikipedia.org/wiki/Metaclass) i.e. the class of a class which is structurally similar to "Kind" though of course the mechanics are quite different.

I still have an old book Putting Metaclasses to Work - A New Dimension in Object-Oriented Programming by Forman et.al somewhere.

There is also the classic The Art of the Metaobject Protocol by Kiczales et.al which is quie relevant here - https://en.wikipedia.org/wiki/The_Art_of_the_Metaobject_Prot...

The key difference is that the Type guys do it at compile time (correctness) while the OO guys do it at runtime (flexibility).

antonvs 40 minutes ago | parent

> These are the constructs we manipulate in our programs, things like 1, 2, True, "hello", etc… In functional programming contexts, they're also called "terms."

This is not correct. Terms are syntactic expressions in a program. For example, 1+2 is a term, but it’s not a value. At runtime, it evaluates to 3. As such, some terms correspond directly to values - like 1 - but other terms represent computations that will be performed at runtime.

tl;dr: terms are a syntactic concept, values are a runtime concept. Terms evaluate to values.

antonvs 7 minutes ago | parent

Following on from the above, this statement is also incomplete at best:

> Types are groups of related values.

This is an operational perspective which misses one of the most important aspects of types: in a statically typed language, types are a way to classify terms, i.e. they're not just about values.

As an example of why this distinction matters, consider this expression: 1 + "hello". In most statically typed languages, this will be rejected at compile time. It doesn't have to be evaluated (i.e. at runtime) to be rejected - it's invalid because the types of the terms - 1 and "hello" - aren't compatible.

This compile-time rejection is only possibly because types apply to terms, and terms aren't values. This is critical to the usefulness of statically-typed languages - without this, they'd have to run the program to detect type errors.

Benjamin Pierce's book "Types and Programming Languages" has some great coverage of this topic.

cat-whisperer 3 minutes ago | parent

I really like the concept of dependent types, all type systems that I use rust or haskell have a very limited set of dependent types, but I do like the things that it let's you do