--- symmetry.pl	2007/08/26 12:17:00	5
+++ symmetry.pl	2007/08/26 14:15:26	6
@@ -30,6 +30,7 @@
 
 my @board = map { split(//) } split(/\n/, $board);
 my @trace;
+my @visited = (' ') x ($#board + 1);
 
 # line length
 my $ll = 8 * 2 + 1;
@@ -53,37 +54,89 @@
 
 sub draw {
 	my $o = 0;
-	my $out;
+	my $out = "\n  " . join('',
+		('0 1 2 3 4 5 6 7 8 | ') x 3
+	) . "\n";
 	while ( $o < $#board ) {
+		my $l = '|';
+		if ( $o % ($ll*2) == 0) {
+			my $y = int($o / ($ll*2));
+			$out .= "$y ";
+			$l = $y;
+		} else {
+			$out .= "  ";
+		}
+
 		$out .= join('', @board[ $o .. $o + $ll - 1 ]);
-		$out .= '   ';
+		$out .= " $l ";
 		$out .= join('', @trace[ $o .. $o + $ll - 1 ]);
-		$out .= "\n";
+		$out .= " $l ";
+		$out .= join('', @visited[ $o .. $o + $ll - 1 ]);
+		$out .= " $l\n";
 		$o += $ll;
 	}
+
+	$out .= "\n";
+
 	return $out;
 }
 
 sub trace {
 	warn "## trace $pos\n";
 	$trace[ $pos ] = $board[ $pos ];
+	$visited[$pos]++;
 }
 
 my ( $tr_x, $tr_y );
+my ( $bl_x, $bl_y );
+
+sub x_y {
+	my $p = shift;
 
-sub pos_x_y {
-	my $y = int($pos / ($ll*2));
-	my $x = int(($pos % $ll) / 2);
+	my $update = 0;
+	if ( ! defined( $p ) ) {
+		$p = $pos;
+		$update = 1;
+	}
+
+	my $y = int($p / ($ll*2));
+	my $x = int(($p % $ll) / 2);
+
+	warn "??? x_y($p) $x,$y tr: $tr_x,$tr_y bl: $bl_x,$bl_y\n";
 
-	$tr_x = $x unless defined $tr_x;
-	$tr_y = $y unless defined $tr_y;
+	if ( $update ) {
 
-	$tr_x = $x if $x > $tr_x && $y == $tr_y;
-	$tr_y = $y if $y < $tr_y && $x == $tr_x;
+#		$tr_x = $x if $x > $tr_x && $y == $tr_y;
+#		$tr_y = $y if $y < $tr_y && $x == $tr_x;
+
+		if (
+			$y < $tr_y
+			||
+			$y <= $tr_y && $x > $tr_x
+		) {
+			( $tr_x, $tr_y ) = ( $x, $y );
+			warn "## UPDATED tr: $tr_x,$tr_y\n";
+		}
 
-	warn "## pos_x_y $pos -> $x,$y\n";
+		if (
+			$x < $bl_x
+			||
+			$y > $bl_y
+		) {
+			( $bl_x, $bl_y ) = ( $x, $y );
+			warn "## UPDATED bl: $bl_x,$bl_y\n";
+		}
 
-	return ($x,$y) if wantarray;
+#		$bl_x = $x if $x < $bl_x; # && $y == $bl_y;
+#		$bl_y = $y if $y > $bl_y; # && $x == $bl_x;
+	
+	}
+
+	warn "## x_y($p) -> $x,$y ",
+		$update ? " tr: $tr_x,$tr_y bl: $bl_x,$bl_y" : '',
+		"\n";
+
+#	return ($x,$y) if wantarray;
 	return "$x,$y";
 }
 
@@ -93,7 +146,7 @@
 	$pos += $move_by[ $step ];
 	trace;
 	push @directions, $step;
-	warn "move $step $step_name[$step] to ", scalar pos_x_y, "\n";
+	warn "move $step $step_name[$step] to ", x_y, "\n";
 }
 
 sub follow {
@@ -114,7 +167,8 @@
 
 	my $old = $trace[ $turn_pos ];
 	$trace[ $turn_pos ] = '?';
-	warn "TEST\n",draw( @trace );
+	$trace[ $pos ] = '*';
+	warn "TEST ", x_y($turn_pos), "\n",draw;
 	$trace[ $turn_pos ] = $old;
 
 	if ( $board[ $turn_pos ] =~ $ok_path ) {
@@ -143,12 +197,21 @@
 
 	$pos = $y * $ll * 2 + $x * 2;
 
-	warn "<<< shape from $x,$y pos: $pos\n";
 	@trace = ($unknown) x ( $#board + 1 );
 	@directions = ();
 	trace;
 
 	my $len = 0;
+	( $tr_x, $tr_y ) = ( $x,$y );
+	( $bl_x, $bl_y ) = ( $x,$y );
+	$step = 0;
+
+	if ( $visited[$pos] > 3 ) {
+		warn "*** shape from $x,$y pos: $pos iterated 4 times, skipping\n";
+		return;
+	}
+
+	warn "<<< shape from $x,$y pos: $pos\n";
 
 	while( 1 ) {
 
@@ -167,23 +230,30 @@
 			warn "find line continuation from $step $step_name[$step]...\n";
 			can_turn( $step - 1 ) || can_turn( $step + 1 ) || die "can't find new direction";
 		}
-		warn draw( @trace );
+		warn draw;
+
+		warn "## tr: $tr_x,$tr_y bl: $bl_x,$bl_y\n";
 
 		if ( $debug ) {
-			warn "## tr: $tr_x,$tr_y\n";
 			print "WAIT> press enter | ",show_directions; my $foo = <STDIN>;
 		}
 	}
 
 	push @shapes_found, { x => $x, y => $y, len => $len, directions => show_directions };
 
-	warn ">>> ended at $pos, line length: $len, directions traversed: ",show_directions,"\n";
-
 	my $tr = "$tr_x,$tr_y";
+	my $bl = "$bl_x,$bl_y";
+
+	warn ">>> ended at $pos, line length: $len, directions traversed: ",show_directions," tr: $tr bl: $bl\n";
+
 	if ( ! grep( /\Q$tr\E/, @shapes_start ) && $tr_x < 8 ) {
-		print "INFO: added top-right $tr\n";
+		warn "INFO: added $tr top-right\n";
 		push @shapes_start, $tr;
 	}
+	if ( ! grep( /\Q$bl\E/, @shapes_start ) && $bl_y < 8 ) {
+		warn "INFO: added $bl bottom-left\n";
+		push @shapes_start, $bl;
+	}
 
 	print "WAIT> press enter"; my $foo = <STDIN>;