Ask HN: Why would anyone choose Haskell to develop applications?

Haskell is the Mercedes Benz of modern PL. There are more advanced/esoteric languages, and there are less advanced/esoteric languages, but in general features developed, explored, and tinkered with in Haskell trickle down to other languages.

It offers less and less practical benefits over other languages because other languages evolve to where Haskell has been.

Haskell is correct, and it forces you to be correct and enforces a kind of clarity of thought that is seldom required from other languages. I think it's something you have to discover for yourself. If you don't see Typescript as strictly better than Javascript, you're probably not going to see the benefits of Haskell over any other language.

All that said, we have to ask ourselves which areas of computing Haskell can be profitably used in to gain the kind of critical mass that other languages have:

- Early programming, analysis, data science, etc -> Python is a better fit because it's easier to pick up, easier to understand, even though it's less correct. People discover libraries about checking types at runtime before they discover then can check them at compile time. Python has long since started it's evolution w/ the typing module.

- Web -> JS, because it's basically the only option. Projects like Elm and Purescript have made small dents, but the most successful cultural descendant of Haskell (if you can call it that) is Typescript.

- Startups -> Ruby/Rails, Django, NestJS, etc. win over Haskell here because you don't need to be right to have a successful startup, you need to find customers and after that product-market fit. Your startup could be airflow+google sheets with all-manual validation and still succeed over the most carefully crafted and bullet proof Haskell code.

- Safety critical systems -> Often are required to be realtime and it's easier to get to the safety requirements in other low level languages with strict procedure/process/standards and guaranteed realtime-capable OSes and tooling rather than using Haskell.

I've written about Haskell in the past (excuse the title):

https://vadosware.io/post/how-and-why-haskell-is-better/

Sometimes yes but for a lot of situations we have better options, like ClojureScript, TypeScript, etc.

Sure. A program with no side effects can't do anything but warm up the computer

Sure, except it should be foldl' instead.

StackOverflow is thataway -->

Edit for reason: https://wiki.haskell.org/Foldr_Foldl_Foldl'

> What features are both present in all of JavaScript/Go/Python and absent from Java/Kotlin that have any relevance to the Gang of Four patterns?

For example:

1. Being able to define a top-level function

2. Being able to return a function

These either shoehorn every codebase into OOP or force the usage of design patterns.

Mind you, it's possible that if you're writing strictly modern Java/Kotlin/whatnot then these are fixed/irrelevant, but that doesn't erase the billions of overengineered lines of code out there.

From [1]:

> Abstract factory adds another level of abstraction to factory method. While factory method abstracts the way objects are created, abstract factory abstracts how the factories are created. The factories in turn abstracts the way objects are created. You will often hear the abstract factory design pattern referred to as a “factory of factories“.

This type of insanity is exactly what the parent is referring to. Layers of needless abstractions that paper over the lack of basic features every other language has.

[1]: https://springframework.guru/gang-of-four-design-patterns/ab...