[Haskell-cafe] simple state monad exercises? (besides labeling trees)

[Matthias Görgens]

> Can someone give some simple common scenarios where the state monad is
> useful, besides labeling trees?

Emulating the VM given in this years ICFP programming contest was also
a good application of the state monad.  Of course you interprate much
simpler language imperative languages, too.  (However that might feel
a bit forced as an exercise.)