Represents the map in which the robot moves.


  my $grid = 'Karel::Grid'->new( x => 10, y => 12 );

The constructor creates an empty grid of the given size.

$grid->x, $grid->y
    my ($x, $y) = map $grid->$_, qw( x y );

Returns the size of the grid.

$grid->at($x, $y)

Returns a space if there's nothing at the given position. For marks, it returns 1 - 9. For walls, it returns "W" (outer walls) or "w" (inner walls).

$grid->build_wall($x, $y)

Builds a wall ("w") at the given coordinates.

$gird->remove_wall($x, $y)

Removes a wall ("w") from the given coordinates. Dies if there's no wall.

$grid->drop_mark($x, $y)

Drop a mark at the given position. There must be an empty place or less than 9 marks, otherwise the method dies.

$grid->pick_mark($x, $y)

Pick up a mark from the given position. Dies if there's no mark.

$grid->clear($x, $y)

Set the given position to empty (" ").