Andy Gill developed HERA which sounds somewhat similar to what you are asking, but I don't know that it would be particularly beginner friendly and I think it was static - i.e. the reduction rules were applied to program source code rather than within an interactive evaluation of a running program. I thought I'd seen more information about it on the web, but all I can seem to find at the moment is this page:
http://www.haskell.org/haskellwiki/Haskell_Equational_Reasoning_Assistant Maybe a debugger like HOOD or HAT would be usefully illustrative for runtime evaluation? I think HOOD is back working with recent GHC's. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
