6 ms·

A bit off topic, but is Haskell viable for production? Or is it just really intended as an experiment? Is it worthwhile to jump into Haskell now, or perhaps one

by nextos 6y ago

A bit off topic, but is Haskell viable for production? Or is it just really intended as an experiment? Is it worthwhile to jump into Haskell now, or perhaps one should look into Idris or Agda? Any companies using Haskell where it has proven a distinct advantage? Ocaml and SML (the former being sadly quite unpopular these days) are an order of magnitude simpler than Haskell. They are easy to master. I have been quite productive with Scala which, while being a member of the ML family, is much more intricate due to OO + FP on top of great Java interop and many Haskell-like features (laziness, monads, lenses...). Haskell doesn't feel the same. I have learned some Haskell over the years. Since I come from a pure FP education (started with SML) and I have lots of type theory background, everything feels familiar, yet I've found it really hard to be productive or to justify the mental overhead of laziness. I have developed some small projects in Haskell, but I haven't found it a productive alternative to the languages above.

the_af 6y ago
> A bit off topic, but is Haskell viable for production? Or is it just really intended as an experiment? It's viable for production and there are businesses which use it, notably fintechs. Also Facebook for some things (Facebook employs Simon Marlow [1]). And I know this is an irrelevant anecdote, but I have a friend who has been working in several startups which use Haskell for the last few years. Like Paul Graham has argued of Lisp, Haskell really is a "secret weapon" and people who use it for production tend to love it. EDIT: a prior version of this post claimed Facebook employed Philip Wadler, which is incorrect. Sorry! I got my wires crossed and confused Philip Wadler with Simon Marlow! [1] https://www.linkedin.com/in/simonmarlow/ https://www.linkedin.com/in/simonmarlow/
- auggierose 6y ago
  Facebook employs Wadler? Since when?
  - the_af 6y ago
    Gah! I meant to say Simon Marlow [1], co-developer of the Glasgow Haskell Compiler (GHC) [2]. Sorry for the confusion, I'll edit my other post now. [1] https://www.linkedin.com/in/simonmarlow [2] https://en.wikipedia.org/wiki/Simon_Marlow
- nextos 6y ago
  > Haskell really is a "secret weapon" and people who use it for production tend to love it That's exactly my question. I'd be really interested in hearing about domains where Haskell is a secret weapon and how it compares to ML family languages and dependently-typed ones.
  - the_af 6y ago
    I'll let people who actually use it -- instead of toy with it, like myself -- answer you. I know many haskellers read HN and have answered similar questions in the past. Like I said, I do know Haskell is used at fintechs (source: a friend whose job is precisely that).
  - ghostwriter 6y ago
    https://news.ycombinator.com/item?id=23367803 https://news.ycombinator.com/item?id=23367803
  - implicit 6y ago
    I did a bunch of professional Haskell work in a prior life[1]. Most of its 'secret weapon' status springs from the way Haskell lets you control side effects. We had a fantastic unit testing harness[2]. With effect tracking, you can arrange for your harness to put precise fences around nondeterministic code. You don't need to rely on experience and discipline to ensure that tests are reliable or fast. The type system does it for you. Effect tracking also makes concurrent code easier to write. You have a great deal of control over how and when threads can be created, and what kinds of logic is permitted on those threads. GHC's IO manager offers green threads and async IO, so rather than a select loop, you just fork threads and perform "blocking" IO calls. You get about the same efficiency as a select loop this way. Lastly, something we learned to appreciate over the years is that Haskell is easier to refactor. When you combine the rigid type system, effect tracking system, and ease of writing unit tests, it becomes very easy to refactor old Haskell. It doesn't really matter how bad the old code was or whether the original author is around to help you at all. If you intend for your product to evolve continuously forever, this is truly a secret weapon. [1] https://andyfriesen.com/2014/03/25/what-its-like-to-use-haskell.html [2] https://andyfriesen.com/2015/06/17/testable-io-in-haskell.html
hazz99 6y ago
Hasura (one of my favourite technologies) is built with Haskell!
tome 6y ago
To answer your questions literally without much nuance: Yes, Haskell is viable for production. There are caveats, as with any other language. Haskell has more caveats that most other languages you would be familiar, but it's nonetheless perfectly suitable in the right environment. No, don't use Agda or Idris in production, they're totally unfit. Agda is not intended to be. Idris may be but it will take 5 or 10 years. The only members of the ML family that I'm aware of are Ocaml and the flavours of Standard ML. Only Ocaml is fit for production.
- mr_custard 6y ago
  > The only members of the ML family that I'm aware of are Ocaml and the flavours of Standard ML. Only Ocaml is fit for production. F# is also a member of the ML family and is totally fit for production.
  - FridgeSeal 6y ago
    F# is the language I want to like, and would like to use in prod, but it constantly feels like the ignored step-child. The REPL is great in theory, but trying to import packages is a nightmare every time I try. Dependencies exist, but they all seem to target wide and inconsistent range of the ecosystem. Want to target dotnetcore 3.1? Good luck have fun: everything you find useful is targeting some combination of standard/framework/core/whatever confusing variant Microsoft decides to come up with this week. If I somehow convinced my co-workers to adopt a language that wasn't C#, I'd point them Rust or Haskell instead.
    - Paradigma11 6y ago
      I totally agree with your points but the situation seems to be improving. With https://devblogs.microsoft.com/dotnet/announcing-f-5-preview-1/ https://devblogs.microsoft.com/dotnet/announcing-f-5-preview... you can import nuget packages in fsx scripts. The dependency situation also seems to grow saner every month. Nevertheless i would still wait another few month for things to stabilize with .net 5.
    - akra 6y ago
embwbam 6y ago
I’ve used it on multiple projects for clients over the last 5 years. These projects were large, made it to production, and were successful. I love it. Once you clear the initial learning curve it feels very productive, and gives you the feeling of always having something more to learn and master.
- nextos 6y ago
  What domains?
MaxGabriel 6y ago
I'm the CTO at Mercury (https://mercury.com/ https://mercury.com/) and we have 100% of our backend written in Haskell. It's gone really well so far. Answering another commenter's question, I would say the "secret weapons" are: 1. Hiring: Haskell is a very in-demand language by very good engineers. For a startup, it's absolutely amazing for recruiting and I can't overstate how important recruiting good people is for a startup. 2. Correctness: Haskell helps you ensure your code doesn't have bugs. For a bank this is fairly important. Some aspects of Haskell that are great for this: algebraic data types ("discriminated unions" in some languages) model business logic quite well, purity makes a function much more of a known quantity, libraries like Persistent ensure type-safe SQL queries, and in general the community cares about correctness. I haven't used the other languages you mentioned, so I can't really speak to a comparison with them. Re: laziness, it's almost never something I think about in practice.
- klipt 6y ago
  > 1. Hiring: Haskell is a very in-demand language by very good engineers. For a startup, it's absolutely amazing for recruiting and I can't overstate how important recruiting good people is for a startup. Although for engineers, supply-and-demand favoring employers typically means it disfavors employees: you may effectively be taking a pay cut to use Haskell compared to more popular languages.
  - lostcolony 6y ago
    Sure, but those that are willing to because they're sufficiently excited about the language means you can have a higher confidence in your hires, since they, A. Know what Haskell is, B. Want to learn it, C. Are willing to take a pay cut to be able to get paid to learn/use it. Very high signal to noise I'd wager. If you're a Java shop, you better be paying higher than market rate if you want to be able to attract good talent, but then you still have to figure out who they are amidst all the mediocre/poor devs, who are interested because of the higher comp. Very low signal to noise. It seems like a less popular language, that has real business value, helps achieve the thing every company that isn't "hire fast, fire fast" tries to do with their hiring policy. It does mean you can't easily hire people who already know the language, so you have to consider the ramp up time, but I don't think that's nearly as painful as many hiring managers seem to think it is.
bojo 6y ago
My company writes and supports a lot of custom Haskell software for our parent, an ISP up in Alaska. What we gain is a high level of confidence in our business logic rules due to strict typing, fewer overall tests, and by avoiding a few small gotchas uncrashable runtimes. Not to say it doesn’t come without problems. Poor IDE integration (I personally don’t care), questionable documentation at times, and a steep rewrite your brain learning curve. Some posts I have written. https://www.alasconnect.com/2018/10/02/introducing-haskell-company/ https://www.alasconnect.com/2018/10/02/introducing-haskell-c... https://www.alasconnect.com/2018/10/04/productive-haskell-enterprise/ https://www.alasconnect.com/2018/10/04/productive-haskell-en... http://blog.bojo.wtf/2020/04/15/is-haskell-a-bad-choice/ http://blog.bojo.wtf/2020/04/15/is-haskell-a-bad-choice/
alephu5 6y ago
I've got a REST API in production linking to postgres and rabbitmq and I'm very happy with the performance and maintainability. The ecosystem is a bit more bare than with other languages like node, python or java but in exchange the paradigm and type-system lets you build safe and well isolated code. In my opinion it's also quite easy to read despite being terse. Despite the complaints the build tooling is good, and there are decent plugins for IDE capabilities although they're a little bit resource hungry. My biggest problem is the lack of component libraries, for example I wanted to use SMTP a little while ago but couldn't find a library compatible with the latest GHC so ended up writing a python script connected to rabbitmq. For business logic involving timezones, currencies, API calls, calculations etc. you're pretty well covered though.

by nextos 6y ago

the_af 6y ago

> A bit off topic, but is Haskell viable for production? Or is it just really intended as an experiment? It's viable for production and there are businesses which use it, notably fintechs. Also Facebook for some things (Facebook employs Simon Marlow [1]). And I know this is an irrelevant anecdote, but I have a friend who has been working in several startups which use Haskell for the last few years. Like Paul Graham has argued of Lisp, Haskell really is a "secret weapon" and people who use it for production tend to love it. EDIT: a prior version of this post claimed Facebook employed Philip Wadler, which is incorrect. Sorry! I got my wires crossed and confused Philip Wadler with Simon Marlow! [1] https://www.linkedin.com/in/simonmarlow/ https://www.linkedin.com/in/simonmarlow/

auggierose 6y ago
Facebook employs Wadler? Since when?
- the_af 6y ago
  Gah! I meant to say Simon Marlow [1], co-developer of the Glasgow Haskell Compiler (GHC) [2]. Sorry for the confusion, I'll edit my other post now. [1] https://www.linkedin.com/in/simonmarlow [2] https://en.wikipedia.org/wiki/Simon_Marlow
nextos 6y ago
> Haskell really is a "secret weapon" and people who use it for production tend to love it That's exactly my question. I'd be really interested in hearing about domains where Haskell is a secret weapon and how it compares to ML family languages and dependently-typed ones.
- the_af 6y ago
  I'll let people who actually use it -- instead of toy with it, like myself -- answer you. I know many haskellers read HN and have answered similar questions in the past. Like I said, I do know Haskell is used at fintechs (source: a friend whose job is precisely that).
- ghostwriter 6y ago
  https://news.ycombinator.com/item?id=23367803 https://news.ycombinator.com/item?id=23367803
- implicit 6y ago
  I did a bunch of professional Haskell work in a prior life[1]. Most of its 'secret weapon' status springs from the way Haskell lets you control side effects. We had a fantastic unit testing harness[2]. With effect tracking, you can arrange for your harness to put precise fences around nondeterministic code. You don't need to rely on experience and discipline to ensure that tests are reliable or fast. The type system does it for you. Effect tracking also makes concurrent code easier to write. You have a great deal of control over how and when threads can be created, and what kinds of logic is permitted on those threads. GHC's IO manager offers green threads and async IO, so rather than a select loop, you just fork threads and perform "blocking" IO calls. You get about the same efficiency as a select loop this way. Lastly, something we learned to appreciate over the years is that Haskell is easier to refactor. When you combine the rigid type system, effect tracking system, and ease of writing unit tests, it becomes very easy to refactor old Haskell. It doesn't really matter how bad the old code was or whether the original author is around to help you at all. If you intend for your product to evolve continuously forever, this is truly a secret weapon. [1] https://andyfriesen.com/2014/03/25/what-its-like-to-use-haskell.html [2] https://andyfriesen.com/2015/06/17/testable-io-in-haskell.html

hazz99 6y ago

Hasura (one of my favourite technologies) is built with Haskell!

tome 6y ago

To answer your questions literally without much nuance: Yes, Haskell is viable for production. There are caveats, as with any other language. Haskell has more caveats that most other languages you would be familiar, but it's nonetheless perfectly suitable in the right environment. No, don't use Agda or Idris in production, they're totally unfit. Agda is not intended to be. Idris may be but it will take 5 or 10 years. The only members of the ML family that I'm aware of are Ocaml and the flavours of Standard ML. Only Ocaml is fit for production.

mr_custard 6y ago
> The only members of the ML family that I'm aware of are Ocaml and the flavours of Standard ML. Only Ocaml is fit for production. F# is also a member of the ML family and is totally fit for production.
- FridgeSeal 6y ago
  F# is the language I want to like, and would like to use in prod, but it constantly feels like the ignored step-child. The REPL is great in theory, but trying to import packages is a nightmare every time I try. Dependencies exist, but they all seem to target wide and inconsistent range of the ecosystem. Want to target dotnetcore 3.1? Good luck have fun: everything you find useful is targeting some combination of standard/framework/core/whatever confusing variant Microsoft decides to come up with this week. If I somehow convinced my co-workers to adopt a language that wasn't C#, I'd point them Rust or Haskell instead.
  - Paradigma11 6y ago
    I totally agree with your points but the situation seems to be improving. With https://devblogs.microsoft.com/dotnet/announcing-f-5-preview-1/ https://devblogs.microsoft.com/dotnet/announcing-f-5-preview... you can import nuget packages in fsx scripts. The dependency situation also seems to grow saner every month. Nevertheless i would still wait another few month for things to stabilize with .net 5.
  - akra 6y ago

embwbam 6y ago

I’ve used it on multiple projects for clients over the last 5 years. These projects were large, made it to production, and were successful. I love it. Once you clear the initial learning curve it feels very productive, and gives you the feeling of always having something more to learn and master.

nextos 6y ago
What domains?

MaxGabriel 6y ago

I'm the CTO at Mercury (https://mercury.com/ https://mercury.com/) and we have 100% of our backend written in Haskell. It's gone really well so far. Answering another commenter's question, I would say the "secret weapons" are: 1. Hiring: Haskell is a very in-demand language by very good engineers. For a startup, it's absolutely amazing for recruiting and I can't overstate how important recruiting good people is for a startup. 2. Correctness: Haskell helps you ensure your code doesn't have bugs. For a bank this is fairly important. Some aspects of Haskell that are great for this: algebraic data types ("discriminated unions" in some languages) model business logic quite well, purity makes a function much more of a known quantity, libraries like Persistent ensure type-safe SQL queries, and in general the community cares about correctness. I haven't used the other languages you mentioned, so I can't really speak to a comparison with them. Re: laziness, it's almost never something I think about in practice.

klipt 6y ago
> 1. Hiring: Haskell is a very in-demand language by very good engineers. For a startup, it's absolutely amazing for recruiting and I can't overstate how important recruiting good people is for a startup. Although for engineers, supply-and-demand favoring employers typically means it disfavors employees: you may effectively be taking a pay cut to use Haskell compared to more popular languages.
- lostcolony 6y ago
  Sure, but those that are willing to because they're sufficiently excited about the language means you can have a higher confidence in your hires, since they, A. Know what Haskell is, B. Want to learn it, C. Are willing to take a pay cut to be able to get paid to learn/use it. Very high signal to noise I'd wager. If you're a Java shop, you better be paying higher than market rate if you want to be able to attract good talent, but then you still have to figure out who they are amidst all the mediocre/poor devs, who are interested because of the higher comp. Very low signal to noise. It seems like a less popular language, that has real business value, helps achieve the thing every company that isn't "hire fast, fire fast" tries to do with their hiring policy. It does mean you can't easily hire people who already know the language, so you have to consider the ramp up time, but I don't think that's nearly as painful as many hiring managers seem to think it is.

bojo 6y ago

My company writes and supports a lot of custom Haskell software for our parent, an ISP up in Alaska. What we gain is a high level of confidence in our business logic rules due to strict typing, fewer overall tests, and by avoiding a few small gotchas uncrashable runtimes. Not to say it doesn’t come without problems. Poor IDE integration (I personally don’t care), questionable documentation at times, and a steep rewrite your brain learning curve. Some posts I have written. https://www.alasconnect.com/2018/10/02/introducing-haskell-company/ https://www.alasconnect.com/2018/10/02/introducing-haskell-c... https://www.alasconnect.com/2018/10/04/productive-haskell-enterprise/ https://www.alasconnect.com/2018/10/04/productive-haskell-en... http://blog.bojo.wtf/2020/04/15/is-haskell-a-bad-choice/ http://blog.bojo.wtf/2020/04/15/is-haskell-a-bad-choice/

alephu5 6y ago

I've got a REST API in production linking to postgres and rabbitmq and I'm very happy with the performance and maintainability. The ecosystem is a bit more bare than with other languages like node, python or java but in exchange the paradigm and type-system lets you build safe and well isolated code. In my opinion it's also quite easy to read despite being terse. Despite the complaints the build tooling is good, and there are decent plugins for IDE capabilities although they're a little bit resource hungry. My biggest problem is the lack of component libraries, for example I wanted to use SMTP a little while ago but couldn't find a library compatible with the latest GHC so ended up writing a python script connected to rabbitmq. For business logic involving timezones, currencies, API calls, calculations etc. you're pretty well covered though.