/*
 * See this URL for lots of information about Picobot:
 *
 *    http://www.cs.hmc.edu/~dodds/Picobot/index.html
 */

/*
 * Be sure to save this file before running!
 */
 
/* 
 * This example zips up and down in the middle of the screen
 *    State 0 is always the starting state 
 */
 
 
1                   // this indicates the map we want to start with

//Go west until we hit a wall.
0 **x* -> W 0 
0 **W* -> X 1 

//Go east until we hit a wall; back up. Head south if we can't back up.
//This is one place where we can try to detect if we're in a north-south
//corridor, and therefore engage the maze solver. Most of the states would
//require an excessive amount of enumeration to check for the corridor case,
//though. Blah.
1 *x** -> E 1
1 NEWx -> S 3
1 *Ex* -> W 2
1 xEWx -> X 6 //Engage maze solver

//Head north if we can; otherwise start going the other direction. If we can't
//go north *or* south, then engage the corridor solver. 
2 x**S -> N 0
2 x**x -> N 0
2 N**x -> S 3
2 N**S -> X 6

//Go west until we hit a wall. Another place where we can try to solve mazes
3 **x* -> W 3
3 *xW* -> X 4
3 xEWx -> X 6

//Go east until we hit a wall; back up. Head north if we can't back up.
4 *x** -> E 4
4 *EW* -> N 0
4 *Ex* -> W 5

//Head south if we can; otherwise reverse direction.
5 ***x -> S 3
5 x**S -> N 0

//Maze-solver: use the right-hand-rule. Four states, depending on which
//direction is to the right at the moment. 6 north, 7 east, 8 west, 9 south.

//"Right" is North; if we have a wall to the north, then go west if we can.
6 NxWS -> E 9           //Completely stonewalled; reverse path
6 N*Wx -> S 8           //Blocked; turn left just this once
6 N*x* -> W 6           //Keep following wall
6 x*** -> N 7           //Turn right

//"Right" is East; try to go north.
7 NEWx -> S 8           //U-turn
7 NEx* -> W 6           //Turn left
7 xE*x -> N 7           //Keep following
7 *x** -> E 9           //Turn right

//"Right" is West; go south
8 xEWS -> N 7           //U-turn
8 *xWS -> E 9           //Turn left
8 **Wx -> S 8           //Follow
8 **x* -> W 6           //Right

//"Right" is South; go east
9 NExS -> W 6           //U-turn
9 xE*S -> N 7           //Left
9 *x*S -> E 9           //Follow
9 ***x -> S 8           //Right