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Subject: 
Re: New Lego challenge !
Newsgroups: 
lugnet.robotics
Date: 
Mon, 13 Sep 1999 07:51:43 GMT
Original-From: 
Laurentino Martins <LAU@MAIL.TELEPAC.PTsaynotospam>
Viewed: 
1944 times
  
At 03:35 13-09-1999 Monday , Mike Poindexter wrote:
> Got it figured out.  Using the principles of right handed recursion, you can
> have the robot follow the right wall and it will eventually get to the light
> and also get out of the maze again.
> 
> Incidentally, right handed recursion will get you out of any labyrinth
> provided that you are not starting inside it already.  If you are already in
> it, it will likely work there as well.  This would then allow the robot to
> work in almost any maze you create.

Yes, unfortunately the current firmware implementation from LEGO doesn't have a call stack, so you can not build recursive routines. :-(

On the other hand I can imagine labyrinths where that bot would never be able to do anything out of them.



Laurentino Martins

[ mailto:lau@mail.telepac.pt ]
[ http://www.terravista.pt/Enseada/2808/ ]



Message has 5 Replies:
  Re: New Lego challenge !
 
(...) Actually you don't need a recursive algorithm to apply the right hand rule. Simply follow either the right (or left) wall and you'll arrive at the exit. For a maze with no exit but a "special point" to reach inside (like Philippe's one), the (...) (27 years ago, 13-Sep-99, to lugnet.robotics)
  RE: New Lego challenge !
 
(...) Hmm, maybe it is finally time to try a real application with pbFORTH. With it's large memory space, you can map out the maze and represent it as a bitmap, or tree of paths. You CAN do recursion in pbFORTH, but it's ugly. I rememeber a thread a (...) (27 years ago, 13-Sep-99, to lugnet.robotics)
  RE: New Lego challenge !
 
(...) This may be a good idea, and in fact it may be a good jump start to many people out there that never tried pbFORTH because the inertia of learning a new language (like me!!). If you can provide a nice implementation of this and explain it to (...) (27 years ago, 13-Sep-99, to lugnet.robotics)
  Re: New Lego challenge !
 
(...) A call stack is not an absolute requirement to do recursive processing, it just makes it easier. I have written recursive processes with only an array. -Wes (27 years ago, 13-Sep-99, to lugnet.robotics)
  RE: New Lego challenge !
 
At 12:52 PM 9/13/99 +0000, you wrote: <snip> (...) The argument quickly turned into one of our definition wars about what exactly is recursion. Joel Shafer joel@connect.net (27 years ago, 13-Sep-99, to lugnet.robotics)

Message is in Reply To:
  New Lego challenge !
 
Hello ! Some of us are looking for new Lego-challenges. So, I created this one, which is called : "the Labyrinthus challenge". "The goal is to build a robot which could enter into a labyrinth (made of black tape on white floor or so) and find it's (...) (27 years ago, 12-Sep-99, to lugnet.robotics)

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