[Haskell-cafe] Generalizing three programs

Hi everyone, I've got an interesting problem here I'm trying to solve. Actually, I've got several problems which seem to have a very similar structure. I want to find a way to abstract them to solve other problems which can be thought about in the same way. Here they are: http://hpaste.org/307 http://hpaste.org/308 http://hpaste.org/309 Note that these are just sketches, the programs aren't done yet. The general structure of the problem is that an object enters a system, interacts with different parts of the system, and eventually leaves, and we want to monitor some statistics about the interaction, so that we can then make some changes, and run it again, and hopefully improve it. Thanks in advance for any suggestions!