Haskell's tools for modularity cut in a dimension you're not used to, and if you're not experienced with it, won't see. Percentage-wise in the last 15 years I haven't spent that much time in Haskell, but it's Haskell's tools I'm missing more often in imperative languages than the other way around. (And note the "more often"; it's not that I never miss more conventional tools in Haskell, it's just that I spend more time missing Haskell tools in other languages.)

> ...I don't see myself using much Haskell precisely because its tools for modularity seem limited.

> Dynamic languages are naturally more modular

Why is that? I'm pretty convinced pure and especially lazy languages allow for great modularity.

See http://augustss.blogspot.nl/2011/05/more-points-for-lazy-eva... for an interesting view on this.

I would think it is because of how "modules" can effectively be "bolted" on top of existing things quite easily.

Consider putting a new "module" on a bicycle. If you were doing it statically, it would have to have the screws in the proper place to be able to attach as it needs. Dynamically, however, you just use a zip tie to hold your piece onto the bike.

To be sure, if you buy a nice bike, many of the common attachments have "static" points where things can be added. If you want to place a holder for a phone, however, you are much more likely to do something that is much more adaptable at fitting things on.

becomes much more easy to bolt on funct

Yeah, Carmack has weight due to his history of being incredibly technical and writing lots of incredibly useful code. Also, he has a huge profile in the industry.

He's been a heavyweight proponent of static typing for a while - 2-3 years IIRC - and so it doesn't totally surprise me that Haskell is up his alley. It's particularly notable that he prefers it as a technical lead as a low-pass filter on bugs.

Tim Sweeney (Unreal Engine) has also written about haskell and specifically STM (http://www.st.cs.uni-saarland.de/edu/seminare/2005/advanced-...) and more recently on dependently typed languages (http://arxiv.org/pdf/1307.5277v1.pdf).

Thank you so much for that second link! I've been interested recently in how dependently typed languages can be made more natural for general-purpose programming, and this looks like a really good read. It gives me hope that it won't be too long before there's a dependently typed language comparable to Haskell in terms of community and ecosystem - in my (limited) experience, Agda and Idris are awesome for theorem proving and for small programs, but they're both a ways off from being usable for large, complex programs, and I feel like a big part of what they're lacking is just well-documented libraries for common operations.

I agree.

When Carmack speaks, I do listen. He's a very good programmer and has the level of experience and technical expertise few will get to enjoy. I think it's awesome to see how far he has come from being a C purist, to C++, and now nice functional languages like Haskell.