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A couple million lines of Haskell: Production engineering at Mercury

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Re: A couple million lines of Haskell: Production engineering at Mercury

#11

Post by verandaguy »

le-mark wrote: post #6

It’s hard to imagine what two millions lines of Haskell could possibly be doing. I mean that’s a lot of code and I have the impression that Haskell is “tight” meaning a little code can do a lot. Maybe they have a lot of libraries to do things like json serializing/deserializing, rest api frameworks, logging etc?

Nit: the quality of a language that you call "tight" is usually called "expressive." You can use few characters to express a relatively very abstract idea.

Some people call this "high-level," too.

I will say, though, that 2 million lines of code is much less code than it sounds like at first glance, especially for a company in a highly-regulated space like finance, plus a few years of progress.

Re: A couple million lines of Haskell: Production engineering at Mercury

#12

Post by dnnddidiej »

matt-noonan wrote: post #5
dnnddidiej wrote: post #3

I think you have to get a Haskell job early in career and stick to Haskell jobs. Breaking in is really hard as you come without experience there will be plenty of others with Haskell experience to compete. And because the jobs are rare if it doesnt work out (company becomes bad to work for or layoff) you can be unstuck (or I guess you would switch to Rust, Scala or F#)

As somebody who has helped hire many Haskell devs, I can say that lots of Haskell experience isn't always a positive. We have to filter carefully to make sure that we end up with developers who want to build real things, not developers who just want to get paid for noodling around with Haskell. As far as I'm concerned, I'd much rather hire somebody with lots of experience building things who ended up coming to Haskel…

Interesting, I guess it then depends on the company (or recruiter) then.

Re: A couple million lines of Haskell: Production engineering at Mercury

#13

Post by [deleted] »

le-mark wrote: post #6

It’s hard to imagine what two millions lines of Haskell could possibly be doing. I mean that’s a lot of code and I have the impression that Haskell is “tight” meaning a little code can do a lot. Maybe they have a lot of libraries to do things like json serializing/deserializing, rest api frameworks, logging etc?

[deleted]

Re: A couple million lines of Haskell: Production engineering at Mercury

#14

Post by 1024bits »

maz1b wrote: post #2

I think perhaps contrary to popular belief, Mercury choosing Haskell and their early leadership having such a storied experience in it probably played some non-insignificant role in their success. As a customer of Mercury, it's truly one of the critical companies my toolkit, and I just can't help but feel that their choosing of Haskell made their progress, development and overall journey that much better. I realize t…

I'd also wager that hiring generalists with no prior experience in the language actually helped them, because they got to instill their culture and style from the ground up with their new hires. Pre vibe-coding, most of those people would'nt have wanted to just jump in and hack away with zero instruction.

Re: A couple million lines of Haskell: Production engineering at Mercury

#15

Post by cfiggers »

threethirtytwo wrote: post #4

I really believe in FP and Haskell but I want to examine this objectively. Empirically speaking is what Mercury done successful truly because of Haskell? Do they have metrics that demonstrates clear superiority along some vectored trait like complexity, bug count, etc? >A couple million lines of Haskell, maintained by people who learned the language on the job, at a company that moves huge amounts of money? The conve…

Without having run the whole company twice in parallel, once using Haskell and again in some other language, and without having measured both runs exactly the same way, I don't think metrics like you're interested in could possibly have sufficient context to mean anything reliable.

Obviously Mercury is successful, and obviously Haskell is how they did it. So it's essential to their success. Would it be instrumental to anyone else's anywhere else doing anything else? Can't possibly know, I don't think.

Re: A couple million lines of Haskell: Production engineering at Mercury

#16

Post by cmrdporcupine »

dnnddidiej wrote: post #3

I think you have to get a Haskell job early in career and stick to Haskell jobs. Breaking in is really hard as you come without experience there will be plenty of others with Haskell experience to compete. And because the jobs are rare if it doesnt work out (company becomes bad to work for or layoff) you can be unstuck (or I guess you would switch to Rust, Scala or F#)

My fear with something like Haskell particularly and with hiring people who really love Haskell is that you risk ending up with a certain kind of personality who fetishizes the tool over the problem.

I've been this person, and I've worked with this kind of person, and been the victim of this kind of person. They love language X, or framework Y, and are convinced that so many problems in front of them are shaped in a way that would be solved through the application of it.

They now have a hammer and they go searching for nails to hit with it.

I've been in shops that used Haskell, and it was... fine? It's I guess nice for people who enjoy writing in it -- I prefer other FP languages personally. I like nerdy things like that and used to hang out on Lambda the Ultimate or whatever. But I don't think there's any real secret powers in Haskell or most other tools. I've been burned too many times by that kind of approach.

Re: A couple million lines of Haskell: Production engineering at Mercury

#17

Post by threethirtytwo »

cfiggers wrote: post #15
threethirtytwo wrote: post #4

I really believe in FP and Haskell but I want to examine this objectively. Empirically speaking is what Mercury done successful truly because of Haskell? Do they have metrics that demonstrates clear superiority along some vectored trait like complexity, bug count, etc? >A couple million lines of Haskell, maintained by people who learned the language on the job, at a company that moves huge amounts of money? The conve…

Without having run the whole company twice in parallel, once using Haskell and again in some other language, and without having measured both runs exactly the same way, I don't think metrics like you're interested in could possibly have sufficient context to mean anything reliable. Obviously Mercury is successful, and obviously Haskell is how they did it. So it's essential to their success. Would it be instrumental t…

I’m asking for solutions and answers. Yeah. I’m aware of how hard it is to get metrics.

You can still compare lines of code and bug rate over the same period of time.

Re: A couple million lines of Haskell: Production engineering at Mercury

#18

Post by cmrdporcupine »

threethirtytwo wrote: post #4

I really believe in FP and Haskell but I want to examine this objectively. Empirically speaking is what Mercury done successful truly because of Haskell? Do they have metrics that demonstrates clear superiority along some vectored trait like complexity, bug count, etc? >A couple million lines of Haskell, maintained by people who learned the language on the job, at a company that moves huge amounts of money? The conve…

It's probably more likely it comes down to: if your programmers are capable of learning and working in Haskell, they're likely a cut above in terms of keenosity and nerdiness and motivation around programming, and you're likely to early-cull the people who just got into CS because mom and dad told them it paid well. That's likely to help produce better overall code health.

Re: A couple million lines of Haskell: Production engineering at Mercury

#19

Post by _qhqq »

dnnddidiej wrote: post #3

I think you have to get a Haskell job early in career and stick to Haskell jobs. Breaking in is really hard as you come without experience there will be plenty of others with Haskell experience to compete. And because the jobs are rare if it doesnt work out (company becomes bad to work for or layoff) you can be unstuck (or I guess you would switch to Rust, Scala or F#)

This happened to me.

I've made all my money over a decade in Haskell. Millions. Paid for all my stuff.

It all started with a recruiter on LinkedIn

Re: A couple million lines of Haskell: Production engineering at Mercury

#20

Post by [deleted] »

_qhqq wrote: post #19
dnnddidiej wrote: post #3

I think you have to get a Haskell job early in career and stick to Haskell jobs. Breaking in is really hard as you come without experience there will be plenty of others with Haskell experience to compete. And because the jobs are rare if it doesnt work out (company becomes bad to work for or layoff) you can be unstuck (or I guess you would switch to Rust, Scala or F#)

This happened to me. I've made all my money over a decade in Haskell. Millions. Paid for all my stuff. It all started with a recruiter on LinkedIn

[deleted]
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