What started as a tradewars clone (emporos,ix) has evolved into a mud. The intent is to write two muds to find the abstraction that makes a mud engine.
Build one to throw away they say, I built two. I was increasingly unhappy with IX, and reduced this unhappiness to the way I was parsing commands. I had been messing around with Earley with the idea of writing a text adventure. What I learned from playing around with Earley convinced me to just commit to a text adventure parser, rather than try to generalize to various kinds of interfaces.