Sunday, April 26, 2009

Quantum analogy

Classical physics is an example of pure functional system — when you measure something, the measurement itself has no side effects.

But in quantum mechanics, when you measure something the very action of measurement affects the object of observation. Probably God used unsafePerformIO somewhere?

Thursday, April 23, 2009

Hac5: the rest of the story (almost)

During the third day I tried to develop juicybar. Started by writing new backend class for dock applications (currently it isn't really a class, but eventually you'll be able to have your information bar using bare X, Qt or GTK+ — whatever you want). We did some bughunting with Wolfgang Jeltsch and Duncan Coutts, which showed what evil things can happen if you don't use threaded runtime. Later I hope to make separate post about the future of juicybar, its problems and features.

I had to leave early, about 4.30 pm, to go to Eindhoven (it's also a topic of another post).

I'd like to thank all the organizers — they did really a great (and huge) work. I was glad to meet all those nice people at hackathon (whose names we all know from haskell-cafe). And of course I'm looking forward to the next Hackathon :-)

Hac5: second day

The second day was mostly the day of the demonstrations.
It began with darcs q&a session driven by Eric Kow. Particularly, I found out that no simple solution to my problem is available yet (although I learned about context files which you can exchange with your buddy and use to make "darcs send" happy).
Atze Dijkstra made an announce of the first UHC release. UHC is Utrecht Haskell Compiler, but since UHC grew out of EHC (Essential Haskell Compiler), jokes about UHC being Unessential Haskell Compiler were popular.

Don Stewart showed the way to visualize Haskell data structures using vacuum with cairo backend, and Christophe Poucet made the same in 3d using Ubigraph backend.

David Himmelstrup told about the current status of LHC.
For me, the most interesting during that day was review of Grapefruit made by Wolfgang Jeltsch. The hard thing about Grapefruit is that it extensively uses type extensions and type-level programming, so Wolfgang tried to explain why those are needed. I guess, "ordinary" haskellers passing by were frightened hearing Wolfgang talking about kind polymorphism (at least, I was).

The day ended with collective dinner.

Friday, April 17, 2009

Hac5: first day results

  1. implemented collision with static body for Hpysics.
  2. wasted several hours looking for a way to combine several event queues in grapefruit, but unfortunately no acceptable solution was found
  3. started to implement juicybar — xmobar rewrite using Grapefruit. Good results so far, I hope to release something at the end of hackathon.

Fun in Utrecht

I wonder, is there a Peyton-Jones shop somewhere?

Grapefruit hacking should really be happening there…

Utrecht: first impressions

After a few hours in Utrecht I definitely love it!

There's enormous number of bikes here. If somebody walks, perhaps his bike is just broken.

And there are canals. I bet they are not worse than Amsterdam ones.

The street I live on — Bekkerstraat.

And my generous host. Thank you, Henk!

Also I had a beer with local haskellers: Eelco Lempsink, Chris Eidhof and Sebastiaan Visser (I forgot to take photo of them, sorry, but they are very pleasant guys!)

Hackathon starts tomorrow today at 10 a.m. See you there!