The solution is simple: use Racket. You see, mzscheme 4 doesn't support any Racket stuff. So when trying to load a Racket library (in this case, "unsafe") it won't be able to find it.

If Anarki wants to support people using mzscheme 4, this line should be changed:

If you're seeing those changes in the diff akkartik linked to, take a closer look. It's just whitespace. ^_^;

Pauan pointed out the "(require racket/unsafe/ops)" line in ac.scm. According to https://github.com/nex3/arc/blame/master/ac.scm, the line was added in this February 2011 commit (well before October!): https://github.com/nex3/arc/commit/cea8a4c5e9d1eb42f54b6c333...

The main point is that you want something that works, right? :) If updating Racket isn't working for you, maybe for now you can revert to an older version of Anarki. The commit before the racket/unsafe/ops one is https://github.com/nex3/arc/commit/b36f223bfba2e12e518fff955..., which you can get to like this:

  $ git checkout b36f223b

  $ git checkout master

Yes, I would like to use something that works, and something that is as latest as possible :) I seem to be using Racket (in the form of plt-scheme) and it seems to work for an older version of arc. The point of my question was if I needed to do something to keep up with the changes made in Arc.

---

"The point of my question was if I needed to do something to keep up with the changes made in Arc."

After running it, I have a few more questions, I hope you aren't frustrated with me yet :)

1. What is the difference between "racket -m -f" (this one doesn't work, but used to work with mzscheme) and just "racket -f"? The manpage asks to visit the webpage and i went to this page to look for help, but I dont seem to be able to locate it: http://docs.racket-lang.org/guide/racket.html

2. In the arc prompt, after loading "news.arc", I would like to run the news server on a different thread, eg: "(= app (thread (nsv)))" (read on the web), but it doesnt return me the arc prompt.

3. Just to test what happens under increased load, I went to localhost:8080 and repeatedly hit the refresh button on my browser. After many repeated refreshes, the news page was no longer served. Here's what was happening in the arc screen: http://pastebin.com/TcBa2SuM and here's the tail of logs/srv-* file: http://pastebin.com/Xiym77sR (i wonder who the strange user 0PgEaESj is :))

2. Hmm, it works for me. Are you sure there's no prompt? Here's how it looks for me:

  $ racket -f as.scm  
  Use (quit) or ^D to quit, (tl) to return here after an interrupt. 
  arc> (load "news.arc") 
  nil 
  arc> (thread (nsv)) 
  #<thread> 
  arc> rm: cannot remove `arc/news/story/*.tmp': No such file or directory 
  load items:  
  ranking stories. 
  ready to serve port 8080 

Only if it's meaningless to invoke a procedure called 'main automatically. :-p

These are the command-line args: http://docs.racket-lang.org/reference/running-sa.html

It came as a surprise that HN serves directly off port 80- wonder how to they manage ssl from arc. I plan to serve via apache rewrite rules (reverse proxy)- and yes, sadly all ips in the arc logs show the local address. Thanks for this link. Also, who is that strange user on my logs (there are different names on different hosts)? :)