In my old job, I used haskell for everything from satellital image analysis to the web frontend, but I didn't tell anyone. Specially I didn't tell my bosses.
When they discovered my functional tendencies, they were upset and worried. They feel betrayed, but it was too late. The company was an "haskell powered company".
I give them an edge over the other companies in the field, but when I leave, they were orphaned and unable to hire a new Haskell programmer (I live in Chile, a very imperative nation).
Too bad for them, but for me, it was "pure" functional fun.
Computers and programming don't have to be so complicated. People make them complicated.
The most challenging task I've done with Haskell, was to find the right combination of parameters in orden to sum an array of satellital images, preserving a set of constrains. I couldn't have dreamed of doing that without Haskell. It was the right choice for the job.
When they discovered the tools I've used, they recognized the problem, but they treated me bad, so I search for another job.
Maintainability is secondary if you can't do the job in the first place. Think about it.
I think that using Haskell in the industry is somewhat irresponsible if you live in a third world nation like Chile. You can't find haskell hackers here! You create maintainability problems!
It is clearly not my fault to be intelligent, know some haskell and live in Chile. Can you blame me?
Any competent manager should lay technology requirements/guidelines before starting any projects and maybe even keep an eye on the codebase if he/she has any coding skills... You happened to work for incompetent people, and you just taught them a lesson about their own incompetence. Thumbs up!
They'll probably waste the next 0-3 years rewriting your shit and you have made another company and several suits hate Haskell. The suits talk to each other, you know.
[and the last conversation i had with someone from u chile's computing dept was on datalog. so it's hard to imagine they wouldn't know about something as popular as haskell. and a friend in the engineering/geophysics dept (don't know the correct name - contract research for mines) uses it. and...]
Out of curiosity, how did you learn Haskell?
If you're able to chat, please drop me a line: firstname.lastname@example.org