Comment by csense | Hacker News Reader

Comment by csense | Hacker News Reader

Haskell is a terrible choice for a production system.

I know well over a dozen programming languages. I have a stronger theoretical background in mathematics, computer science, and compiler design than most web developers. But Haskell has always been utterly mystifying to me.

I've attempted to learn Haskell several times, and I've had monads explained to me several times right here on HN -- but I simply don't seem to be able to wrap my mind around the concept.

To be sure, if I had a year or so to devote to studying the theory behind Haskell's type system, I might indeed become more productive writing web applications in Haskell. And I don't doubt that there are certain problems in logic programming or language theory for which Haskell provides useful concepts and powerful tools, to the point where the solutions to important problems may have trivial implementations.

I've always thought that a major problem with Haskell for web development is: (A) You'll have difficulty finding people who both know Haskell and are interested in web applications, and (B) you'll have difficulty training web developers in Haskell. The author of the article apparently has a training process that gets around (B), and I'd kind of like to know what it is -- a way to learn Haskell without a ton of study.

I've seen experienced programmers failing at learning Haskell for the same reason experienced programmers fail at learning Vim, the initial learning curve is very steep, and they don't see the value on climbing that wall. Now, if you know Vim, ask yourself, was it worth it? I'm convinced 99% of people would say yes. It is the same with Haskell, all those seemingly complex concepts come with a big reward.

Learning Haskell is easier with a strong functional programming background; sadly CS students don't learn much about FP, so having lots of experience in CS and compilers won't necessarily put you in a better position than somebody who has no formal background in CS but lots of programming experience.

A math background on the other hand should help you. Learn about how category theory is applied in Haskell, and you're already half way there. Monads are just a piece of the puzzle.

I do agree with your last three points. I haven't used Haskell in production, so my experience in "real world Haskell" is limited, but it has helped me immensely in my daily work with other languages. Haskell forever changes the way you think and approach problems, just like Vim changes the way you write and edit code; it will make you a better programmer.

> the same reason experienced programmers fail at learning Vim, the initial learning curve is very steep, and they don't see the value on climbing that wall.

This is definitely me. I only got really into Linux with Debian-like systems after Nano became those distributions' standard editor. I know the bare minimum about vim for occasional, minimal editing of configuration files. I only ever use it when I'm stuck with a rescue prompt or some third-rate distro that has nothing else. Usually one of my first goals is to get either a GUI, or file transfer capability, or a package manager up and running; then I stop using it.

"I only got really into Linux with Debian-like systems after Nano became those distributions' standard editor."

I'd recommend learning an editor that has any sort of power - vim, emacs, or something lesser known. Trying to get anything done in nano is like pulling teeth. Yeesh.

Vim is multi-platform, and there are GUIs for Vim, particularly GVim and Macvim, where you can use the mouse, and copy/paste, etc, just have to do it the Vim way. You gave up too early, Nano isn't even close; it's like comparing Notepad to Notepad++. Give both Haskell and Vim another chance.

Haskell is something that really needs to be used in order to "learn" it. I didn't learn monads by study/reading, I learned them by just using Haskell for real-world projects.

We use Haskell for all our production systems and it is great. Maintenance is MUCH easier in Haskell and it's usually quite simple for new people (with Haskell experience) to get up to speed with a project. We even had a situation where one guy was able to make a highly nontrivial refactoring to a several thousand line project that he had no prior involvement with. It took him a few hours to do the refactoring and once he got it compiling it worked the first time. We are convinced that this feat would have been impossible in any other mainstream language.

It's a huge help to ask a newcomer to start off by make changes to an already-established project that has best practices and idioms already sorted.

If you just start with the full language, there are just too many ways to solve every problem and it's not clear which is better for your particular use case. It's a bit like Perl, except moreso: even basic flow control is a library.

I found Haskell was not that hard. But I did try to learn by reading Learn You a Haskell twice and gave up.

When I really learnt it, I treated it like I would any other language: I tried to write nontrivial programs in it, in my case the 2048 game. I learnt Monads by adding real randomness to the game.

So I would say the main problem with Haskell is that people treat it like something special, and not like any other language.

"I've had monads explained to me several times right here on HN"

Well, let's add one to the pile, though I second the "use some monads" recommendation. This is one perspective; there are others:

Monad is an interface. It is used when reifying certain kinds of context to give a standard way of chaining those contexts. That reification means 1) you can talk explicitly about those contexts, and 2) the type system can enforce more rules around those contexts. The abstraction provided by the interface means we can hide away a lot of the plumbing.

The Monad interface is defined in terms of a type constructor; that is, a type-level function that takes a type as an argument and produces another type - like a C++ template with one argument. There is a sense in which the monad "wraps" the "inner" type, though for some monads this is metaphorical at best. Still, it provides a vocabulary.

I'm sorry you're only now realizing that just having a bunch of credentials doesn't mean you're a genius. It just means you took the time to study a few specific things in-depth.

Sadly there is no way around actually taking the time to try and understand something in order to understand it. I guess we need to perfect the art of brain transplants.

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