[Haskell-cafe] Generalizing three programs

[Andrew Wagner]

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!