[seddona]

As a counterpoint - at CircuitHub, we migrated from NodeJS / Angular to Haskell / Elm and couldn't be happier.

I think a core reason for our success is that we built our team from experienced developers that had built large applications in other languages. Then arrived at Haskell as a better solution.

I have heard some negative experiences that I would attribute to a few different factors.

1. Lack of Haskell experience in the early team. 2. Lack of experience building large real-world applications (too academic) 3. The startup/group didn't achieve product-market fit, and Haskell was scapegoated.

None of these problems are Haskell specific, just run of the mill team issues.

[sokoloff]

How common is it for the same person to have both strong Haskell experience and experience building large real-world applications?

I’ve tried to find a way to use Haskell (lacking strong experience there, but with lots of large app experience), and I’ve not managed to find a situation where pulling the trigger makes sense because of the risk of getting “stuck” with a poor path out.

[matt-noonan]

> How common is it for the same person to have both strong Haskell experience and experience building large real-world applications?

I would conjecture that it is more common than what you’d expect from random chance. In my case, I picked up Haskell only after building large systems in C++, Objective C, Lisp, and Python. The draw was that Haskell let me express the kind of system invariants that make it possible to reason about a large codebase.

Since then I’ve written production Haskell in three different companies, none of which appear on this list.

[seddona]

Maybe try contributing to a large Haskell codebase first to get a feel for what Haskell is like in in-the-large and gain some comfort.

I'll add this problem is not at all Haskell specific. If you put an experienced Java developer to work architecting a large Python application where they have no prior Python experience you are going to experience similar problems. I'd say the problem is perhaps a bit more acute with Haskell as the paradigm is likely more different to the prior language. So if possible get at least one person on your team that has experience with a large Haskell app and pair them up with other devs.

[FpUser]

In tech world languages are like a religion. Their choice does not really have to make sense. Hence unless it is 100% total proven failure the affiliates will try any means to protect/advocate/spread whatever language they like.

[Koshkin]

This is an inconvenient truth.

[gridlockd]

Requiring a team made out of wizards to successfully launch a product is a huge downside though.

Pretty much anything you do in NodeJS/Angular is run-of-the-mill stuff that your run-of-the-mill hires should be able to work on.

[seddona]

We definitely could have built our product using more mainstream languages. I wouldn't, however, say we required a team of wizards, just good developers that prefer to work in Haskell if possible.

[crimsonalucard]

True but run of the mill languages like this always tend to culminate in codebases that are hard to maintain and necessitates an eventual rewrite due to accumulation of complexity.

Haskell is hard to learn and hard to find developers for, but the trade off is incredible safety and a type system that promotes good design and easy refactoring of inevitable design flaws.

To achieve such a thing with other languages you need a highly disciplined team/culture and you need lots of time (meaning less hard deadlines and time crunches) and willingness to invest time into refactoring.

[gridlockd]

> True but run of the mill languages like this always tend to culminate in codebases that are hard to maintain and necessitates an eventual rewrite due to accumulation of complexity.

I'm reluctant to believe that Haskell magically protects you from that, but let's suppose it was true. What if my run-of-the-mill gang can rewrite the project three times over before your wizards have congregated to sing their first incantation?

> Haskell is hard to learn and hard to find developers for, but the trade off is incredible safety and a type system that promotes good design and easy refactoring of inevitable design flaws.

Again, I'm reluctant to buy into that. Even if that was true, unless you're writing Haskell in a vacuum, you're going to have to interface with various other horrible pieces of technology that will throw a wrench into your beautiful pure design.

Dealing with the ugly bits while maintaining composure is what makes the difference between a really good engineer and somebody who just wants to program. That quality is invaluable, but you're likely not going to develop it by programming in a language that you enjoy.

[crimsonalucard]

>I'm reluctant to believe that Haskell magically protects you from that

i can only show you the door you have to walk through it.

>What if my run-of-the-mill gang can rewrite the project three times over before your wizards have congregated to sing their first incantation?

The 3rd rewrite of your nodejs app still has technical debt. It still has flaws and still is buggy. Every time you redo it, you repeat the same mistakes over and over and over again never knowing how to make things better. You are doomed to participate on an endless cycle of rewrites as people of every generation reinvent the wheel with a new framework and new mistakes never converging on a better solution.

It's a myth that Haskell is slower. The speed I would say is the same because Haskell you would require significantly less testing and validation.

>Even if that was true, unless you're writing Haskell in a vacuum, you're going to have to interface with various other horrible pieces of technology that will throw a wrench into your beautiful pure design.

You do that anyway. At least keep one section of your stack safe and nice. Haskell.

>Dealing with the ugly bits while maintaining composure is what makes the difference between a really good engineer and somebody who just wants to program. That quality is invaluable, but you're likely not going to develop it by programming in a language that you enjoy.

Haskell is about safety and good design. If these two things are not critical to your program, then you shouldn't go the way of Haskell. If it is, Haskell is one of the best technologies to meet that requirement while not costing too much in performance / speed of development.

If Haskell has a critical flaw it's the learning curve. But that's a one time deal. Once you get past the curve you're good. Also don't call us wizards. We're not... Haskell isn't that hard. Anyone can learn it, this isn't like quantum physics. Becoming an expert database SQL ninja admin on postgresql is probably just as hard as becoming one on haskell. haskell like sql is just a bit challenging because it's expression based as opposed to imperative like python.

[goto11]

> The 3rd rewrite of your nodejs app still has technical debt. It still has flaws and still is buggy.

Are you seriously suggesting that code written in Haskell cannot have bugs, flaws and technical debt?

> Every time you redo it, you repeat the same mistakes over and over and over again never knowing how to make things better.

Am I to understand that people writing in JS cannot learn from mistakes, but people writing in Haskell can?

Haskell is a cool language, but you are not helping its image by such outlandish claims.

[crimsonalucard]

>Are you seriously suggesting that code written in Haskell cannot have bugs, flaws and technical debt?

No way. Not at all. I am suggesting that Haskell code will have significantly less bugs and less technical debt not none. I am not making a single outlandish claim.

>Am I to understand that people writing in JS cannot learn from mistakes, but people writing in Haskell can?

Yeah. Every couple years people who write JS come up with new garbage frameworks that don't really move the needle forward. React, angular, vue, jquery.... different flavors of the same issue while fixing old problems and creating new ones. Of course their's slight progress forward with things like type script but overall I see the same mistakes being repeated every generation. History repeats itself is a popular saying because there are just as many people who don't learn as there are people who do.

>Haskell is a cool language, but you are not helping its image by such outlandish claims.

Maybe you should understand my claim before calling it outlandish. Significantly less bugs and less technical debt is a real thing, but nowhere did I claim ZERO. You still need unit tests and you still need to think about your design.

Perhaps it's my fault. My comments deliver a perception about haskell that is false. I'll think about it, but in no way did I intend to imply anything outlandish about haskell.

[gridlockd]

> The 3rd rewrite of your nodejs app still has technical debt. It still has flaws and still is buggy. Every time you redo it, you repeat the same mistakes over and over and over again never knowing how to make things better.

Oh really? Well that's good news too, because now I can just save myself those rewrites, because they're pointless. That's a 3x improvement right there.

> It's a myth that Haskell is slower. The speed I would say is the same because Haskell you would require significantly less testing and validation.

If you have wizards, that is.

> Haskell is about safety and good design. If these two things are not critical to your program, then you shouldn't go the way of Haskell.

They certainly aren't critical to your run-of-the-mill NodeJS/Angular project which, I must remind, is the alternative that we are discussing here.

> If Haskell has a critical flaw it's the learning curve. But that's a one time deal.

No, it's a "one time per hire" deal.

> Also don't call us wizards. We're not... Haskell isn't that hard.

I'm certainly not calling all Haskell programmers wizards, I'm referring to that "team of experienced developers that had built large applications in other languages (and then arrived at Haskell as a better solution)" that the original commenter saw as a requirement for success.

Of course it's not impossible to assemble such a team for a run-of-the-mill project. It's just impractical.

> Becoming an expert database SQL ninja admin on postgresql is probably just as hard as becoming one on haskell.

See, that's another kind of expert that I definitely don't want to need on the team. I want people who have a basic understanding of SQL, with a reluctance to learn the ins and outs of it. That'll dramatically lower the chances of them trying to be smart with SQL.

[Quekid5]

> If you have wizards, that is.

I'd just like to call attention to this. There is no wizardry to learning (basic) Haskell very well, i.e. to such a degree that using an Elm-like library would not be an obstacle to getting the job done.

You may not ever learn advanced Category Theory, but that -- contrary to popular belief -- is not actually necessary. You may end up using some libraries that use Category Theory at an advanced level (lens), but at absolute worst we're talking learning to parse compiler error messages that are about 1-5% of what a C++ compiler will spit out at you.

Also... when did we want to stop learning?

[crimsonalucard]

>Oh really? Well that's good news too, because now I can just save myself those rewrites, because they're pointless. That's a 3x improvement right there.

No dude don't even write it because likely it will be garbage. If you truly believe that nodejs apps don't need to be rewritten go to Uber. They never rewrote their entire nodejs code base in Golang.

>If you have wizards, that is.

Haskell isn't all wizards. It's just regular people who learned something different.

>No, it's a "one time per hire" deal.

Same with almost every other language that isn't popular yet. Rust and golang and kotlin and swift all went through this. The goal of any language is to become popular enough to get past this.

>I'm certainly not calling all Haskell programmers wizards

Then what is the big deal. If we aren't wizards then it's easy to learn. Programmers learn new languages all the time. Learning Haskell is just slightly more challenging and not a huge drain on productivity. Spend a couple more months training new developers in exchange for a 90% reduction in bugs and much better design.

>See, that's another kind of expert that I definitely don't want to need on the team. I want people who have a basic understanding of SQL, with a reluctance to learn the ins and outs of it. That'll dramatically lower the chances of them trying to be smart with SQL.

Eventually for certain queries you will have to get clever and write queries to optimize. Additionally to serve certain architectures you have to know a lot about the inner workings of the database and how to manipulate the api to get the performance needed at the lower level. An expert has no trouble with this and is an asset. This isn't about getting clever or doing tricky things with syntax just to be clever... this is about inevitability of the fact that a client will want to ask a question to a database that has grown so complex it is not straightforward to answer his question in a performant way. This is extremely common even for your run of the mill web app company.

But that's besides the point. I'm comparing haskell to SQL because it's a similar learning curve. Both are expression based languages. In fact I would argue that Haskell is EASIER then SQL due to the type checking.

Learn the language if you really want to understand our perspective. I use to be in that camp of why learn a freaking language when it's barely used, but that changed once I learned haskell.

[the_af]

> What if my run-of-the-mill gang can rewrite the project three times over before your wizards have congregated to sing their first incantation?

Is there any evidence Haskell projects take longer than projects done in "run of the mill" languages?

[galaxyLogic]

Yes and you can have your monads too, in JavaScript

[crimsonalucard]

You can have monads in any language. If you have a functor you have a monad. If you have a type that wraps or encodes another type in a lossless or lossy way you have a functor. Therefore a functor exists in any language with compound types therefore every language that has compound types has monads.

The difference is Haskell makes these concepts explicit.

[galaxyLogic]

I would be interested in learning more about how does Haskell make monads "explicit"?

Does Haskell have the keyword "monad"?

Does Haskell have support for ensuring that monadic laws hold for any prospective monad?

[crimsonalucard]

Haskell provides it as an "interface" in the "standard library"

http://hackage.haskell.org/package/base-4.12.0.0/docs/Prelud...

You have to implement the methods but things like associativity and the existence of identity are not enforced.

Additionally all IO functions in haskell are monads with a return type that is a functor called IO that can contain another type or nothing. You cannot print something to console without invoking a monad in haskell. The clever thing about the IO functor type is that it can only be instantiated by a true IO function that touches some external thing, there is no other way to instantiate this type.

So for example the Instantiated type IO(int) cannot exist unless someone called a function that receives integers from a socket. And to extract the int from the functor you have to use the monadic bind operator.

[galaxyLogic]

I see. Thanks. So the library-interface named "monad" includes the special machinery for programming monads. Libraries written in other languages could provide something similar, I assume.

[Koshkin]

But see Greenspuns Tenth Rule of Programming (substitute Haskell for Common Lisp and JavaScript for Fortran).

[gridlockd]

I do not believe that the rationale behind this rule applies to any dynamic/scripting language.

It would apply to Haskell though, unless Haskell itself works well as a scripting host.