From: the_evil_trembles@yahoo.com   
      
   I'm trying to write this prolog interpreter but i encountered a   
   problem. Let's say i'm evaluating a rule and i found a possible   
   solution. How will i store my current position in the parse tree of   
   the rule if i'm going back to it when i backtrack? I'm thinking of   
   using a stack but then, i have no idea how to use it for this   
   application. Do you guys have any opinions on the matter?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)