[nbouscal]

> Don't things get messy and ugly as the pure world of Haskell is being tainted?

Haskell is excellent at handling state. "Pure" doesn't mean no state, it means all state is handled explicitly in a type-safe way.

> How do I optimise Haskell code without having studied the language for decades?

It requires learning some new things, but honestly when I worked at a company that used Haskell I didn't really have to worry about this much. You occasionally make some things strict and there are some good heuristics about when this is needed, but overall it just didn't come up often.

> I had a lecture where we were taught Haskell, so I know the language

No you don't. You can learn Python in a lecture if you know Ruby; you can't learn Haskell in a lecture unless you already knew SML or OCaml, and even then probably not.

> The fact that everything is a linked list (bad for caching & performance) and everything gets copied around really turns me off.

Everything isn't a linked list in production code. It's easy to swap lists out for vectors wherever it's correct to do so, because you can write almost all of your code generalized to the necessary type class rather than specific to one single container type. Real Haskell code performs well, poorly-performing code is just used for examples when teaching beginners because it's easier and introduces fewer things at once.

[axlprose]

> you can't learn Haskell in a lecture unless you already knew SML or OCaml, and even then probably not.

I just want to emphasize this part because it's really quite true, as someone who came to it from F#/OCaml.

The thing with learning "haskell", is that there's faar more to it than learning the basic language constructs. You can learn haskell the language in about a day, but you can't really learn haskell the paradigm/philosophy/mathematical discipline in a day, much less actually program haskell that quickly.

That being said, it's not as difficult as it's made out to be, the mountain you need to climb is much shorter than people realize. The issue is largely one of jargon, and getting used to using and thinking in all the new terms and concepts that really have few equivalents in other languages.

[jack9]

> The thing with learning "haskell", is that there's faar more to it than learning the basic language constructs

That would be a compelling reason as to why it's not popular. This basically means your programming experience is not transferable, leaving it as a weird side language that some people stumble into due to uncommon factors.

[axlprose]

Oh it almost certainly is the main reason why it isn't popular. Then again, that is also the same reason why abstract mathematics in general isn't popular.

Saying the experience is "not transferable" is looking at it the wrong way. Learning the discipline behind haskell isn't even remotely the same kind of beast as learning how to use a niche legacy framework in COBOL for example.

It's a lot more akin to learning to read human language for the first time, because all it's doing is familiarizing you with patterns that exist in code and computation, independent of Haskell. The actual language part of the haskell equation is literally the least relevant/significant, because what it teaches you is to recognize mathematical/computational patterns that you can find in any language, despite the difficulty of expressing some of those concepts succinctly in some languages (e.g. java).

The biggest thing that's 'not transferable' is the ability to communicate the high level patterns to others who haven't gained literacy with that particular branch of mathematics/CS yet. But that's true of all sciences and mathematics. You can call it a "weird side language", but that's kinda doing it a disservice as a language that's intended to express complex relationships and computational patterns in the most general way possible.