I have an implementation of a state space search package that includes A*. I haven't used it on PLT Scheme V4.0, but it shouldn't be hard to convert. Unfortunately, I'm traveling this week and don't have it on my laptop. I'll send it to you off-line later in the week if you haven't found anything else in the meantime. The other Doug in the mailing list <div class="gmail_quote">On Mon, Apr 27, 2009 at 3:09 PM, Doug Orleans <<a href="mailto:dougorleans@gmail.com">dougorleans@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Is there an implementation of the A* search algorithm in PLT Scheme? There's a PLaneT package for Dijkstra's algorithm, but I didn't find A*. If not, I'll probably use the dijkstra package as a starting point, unless someone has a better suggestion. --<a href="mailto:dougorleans@gmail.com">dougorleans@gmail.com</a> _________________________________________________ For list-related administrative tasks: <a href="http://list.cs.brown.edu/mailman/listinfo/plt-scheme" target="_blank">http://list.cs.brown.edu/mailman/listinfo/plt-scheme</a> </blockquote></div>