On Mon, Sep 9, 2013 at 2:57 PM, Paul Johnson <paul at pjcj.net> wrote: > On Mon, Sep 09, 2013 at 01:30:00PM +0000, Dave Hodgkinson wrote: >> Prolog. Facts and rules then go solve. > > no Actually, Prolog was my first thought too. The major limitation is fallback behaviour. James