Somewhat tangential, but the only software I know of that's written in Haskell is ImplicitCAD https://implicitcad.org/
Lispers hailing macros and metaprogramming cannot understand that power is also the very thing that makes jumping from project to project difficult, I have no intention of relearning your cleverly designed DSL or new extensions.
There's a reason why Java or PHP have plenty of widely used killer software, while monocle-wielding lispers and haskellers have very little to show after many decades.
It's not FP being the issue, it's just that their power attracts crowds interested in code more than the features/business/product.
I don't blame them, I love Haskell and Racket but I think very few teams can scale and make the compromise worth it.
In one such system I built had the main (REST API exposing) backend implemented in Kotlin with a separate application in Haskell doing a complex set of maths driven business rules against GIS data to calculate area specific prices.
The amount of IO on the Haskell side was fairly minimum and abstracted away quite nicely.
Haskell allowed expressing all complexity in a way that was easy to audit and translate from business/data analyst requirements.
Would do again :-) But only with the correct amount isolation so you can lean into Haskell's strong sides.
Co-Star, the astrology SaaS, is apparently written with a Haskell backend. I'd love to have seen the casting call for that.
I believe the Mercury bank also runs most of their backend stuff on Haskell. Functional languages in general are surprisingly common among financial investment firms.
Some of Target's stuff is written in Haskell. I think there was at least one big Facebook project that was written in Haskell, but they may have moved away from it by now. Awake Security does some Haskell stuff.
One thing which might be surprising is Haskell is apparently quite strong for general backend web dev.
Yep. Mostly because of the https://www.servant.dev/ framework (but see also IHP, Yesod, and other frameworks). Servant lets you declare your HTTP API at the type level, and then it will infer the correct types for your endpoint handlers. You can also extract OpenAPI specs from it, generate clients for Haskell or other languages, etc.
My current employer, Bellroy, uses Haskell for pretty much all new code and Servant for all new HTTP APIs. https://exploring-better-ways.bellroy.com/our-technology-sta... is an older post discussing the shift to Haskell. We've found Haskell code to be much more compact than the equivalent Ruby, and significantly more robust.
I think they were using Agda or something too for a while, but it appears I can't find what I'm thinking of on their site anymore. Really interesting guys if you're located in the Baltic states.
They have a page about it: https://www.costarastrology.com/why-haskell/
It does one of the things I find most annoying about Haskell programmers, which is that they think the language is magic just because it has ADTs.
> HASKELL MAKES ILLEGAL STATES UNREPRESENTABLE.
That's not true!
It's especially not true for numeric programming, Haskell really doesn't provide good support for that. Basically only Ada and dependent-type languages do.
https://hackage.haskell.org/package/clash-prelude-1.8.2/docs...
How it compares to Ada though, I could not say.
hledger - a plain text accounting tool
Private messenger for desktop and mobile platforms. It's mostly written in Haskell except for UI.
> cpp-for-mobile > Template for cross-platform mobile app with native UIs and C++ core
Their flake.nix indicates they use Haskell to generate cross compiled shared library for Android, iOS, Mac, Linux and Windows.
I am not expert in Nix but at high level I can see they are indeed using Haskell.
Goes to show that success is not determined by technology.
There are plenty of interesting Haskell programs (e.g. Xmonad, Darcs), but a lot of people explicitly use them because they're Haskell.
Pandoc, on the other hand, is useful to pretty much anyone who has ever needed to convert documents. It's one of the first things I install on most computers.
also http://detexify.kirelabs.org/classify.html was surprisingly useful in university
I tried it on couple of one liners and it found a couple of potential problematic points, one for each one liner.
CADQuery/build123d is the other big one I'm interested in.
https://wiki.haskell.org/Haskell_in_industry
Imagine a "Go in industry" page. Even a "Rust in industry" would be laughable at this point.
Ok I'm maybe being a little unfair, but you get the point.