Clojure caching took me like a month max.
Obviously, you can choose whatever you like, it's your company. I'm just explaining what the best solution was for the many students and young programmers who visit hacker news. Clojure is not it for all the reasons I mentioned. And if people think C is hard, practice it. Read Zed's book and do Project Euler problems with it until you feel comfortable with it. It's an essential tool everyone must know how to reach for.
It might not impress their programmer friends, but it'll impress their accountant.
If impressing accountants is the goal of what we do, then the whole thing should have been outsourced overseas.
I read their requirements in the blog post. They need fast access to SVN and Git internals to store off metadata. Based on that it's really not hard to determine what to use to solve this problem. There may not be one exact right answer (in fact, I suggested two), but there is a direction that makes sense and one that does not.
The real disservice to those coming up in this industry is reading blog post after blog post on Hacker News with people looking for "excuses" to use random languages they're interested in playing with. The answer to most of these problems is to use something really boring and straightforward, like C, C++ or Java. I guess I've worked too many places where legacy code becomes a huge burden because one guy wants to play around with X one time. The funny thing is, I see these same guys go onto the next place and do it there.
Can you elaborate on why you think it's a bad choice?
That's still a widely held view, and maybe even a majority, but probably not on HN. (see pg's Beating the Averages essay: http://www.paulgraham.com/avg.html)
Not following what you mean. Do you mean that I do expect people to learn stuff, or that I don't expect them to learn stuff in order to do their job?
Favoring "little to no new concepts" at least suggests a bias against certain kinds of learning. Sometimes learning a new concept is the best way to solve a problem.