A Java-based graphical observation event viewer, building on Andy Gill's Hood (Haskell Object Observation Debugger). There are some interesting examples on the home page.
I found this via an interesting discussion on the Haskell mailing list.
It raises an intersting point. Lazy evaluation can cause some unexpected results. In this case, the problem looked like coming from a non tail-recursive foldl. In fact the problem was that the operator passed to foldl wasn't strict. We disucssed some other non intuitive aspects of FP in the past.
Posted to functional by Ehud Lamm on 2/26/01; 8:14:56 AM