--- symmetry.pl	2007/08/26 09:20:07	2
+++ symmetry.pl	2007/08/26 10:26:13	3
@@ -27,39 +27,39 @@
 _BOARD_
 
 my @board = map { split(//) } split(/\n/, $board);
+my @trace;
 
 # line length
 my $ll = 8 * 2 + 1;
 
+my @step_name = ( qw/right down left up/ );
+my @move_by = ( 1, $ll, -1, -$ll );
+my $step = 0;	# right
+
+# offset 0, top-left corner
+my $pos = 0;
+
+# unknown trace position
+my $unknown = ' ';
+
 sub draw {
-	my @board = @_;
 	my $o = 0;
 	my $out;
 	while ( $o < $#board ) {
-		$out .= join('', @board[ $o .. $o + $ll - 1 ]) . "\n";
+		$out .= join('', @board[ $o .. $o + $ll - 1 ]);
+		$out .= '   ';
+		$out .= join('', @trace[ $o .. $o + $ll - 1 ]);
+		$out .= "\n";
 		$o += $ll;
 	}
 	return $out;
 }
 
-print $board, draw( @board );
-
-my @step_name = ( qw/right down left up/ );
-my @move_by = ( 1, $ll, -1, -$ll );
-my $step = 0;	# right
-
-# offset 0, top-left corner
-my $pos = shift @ARGV || 0;
-
-my @trace = ('x') x ( $#board + 1 );
 sub trace {
-	warn "trace $pos\n";
+	warn "## trace $pos\n";
 	$trace[ $pos ] = $board[ $pos ];
 }
 
-warn draw( @trace );
-trace;
-
 sub move {
 	warn "move $step $step_name[$step]\n";
 	$pos += $move_by[ $step ];
@@ -100,25 +100,47 @@
 	}
 }
 
-while( 1 ) {
+sub shape {
 
-	my $next_pos = $pos + $move_by[ $step ];
-	warn "in loop - pos = $pos next_pos = $next_pos step = $step $step_name[$step]\n";
+	my ($x,$y) = @_;
 
-	if ( $trace[ $next_pos ] ne 'x' ) {
-		warn "position $next_pos re-visited, exiting\n";
-		last;
-	} elsif ( $board[ $next_pos ] =~ $ok_path ) {
-		warn "OK next_pos = $next_pos b($board[$next_pos]) t($trace[$next_pos])\n";
-		move;
-		can_turn( $step + 1 );
-	} else {
-		warn "find line continuation from $step $step_name[$step]...\n";
-		can_turn( $step - 1 ) || can_turn( $step + 1 ) || die "can't find new direction";
+	$pos = $y * $ll * 2 + $x * 2;
+
+	warn "<<< shape from $x,$y pos: $pos\n";
+	@trace = ($unknown) x ( $#board + 1 );
+	trace;
+
+	my $len = 0;
+
+	while( 1 ) {
+
+		my $next_pos = $pos + $move_by[ $step ];
+		warn "in loop - pos = $pos next_pos = $next_pos step = $step $step_name[$step]\n";
+
+		if ( $trace[ $next_pos ] ne $unknown ) {
+			warn "position $next_pos re-visited, exiting\n";
+			last;
+		} elsif ( $board[ $next_pos ] =~ $ok_path ) {
+			warn "OK next_pos = $next_pos b($board[$next_pos]) t($trace[$next_pos])\n";
+			move;
+			$len++;
+			can_turn( $step + 1 );
+		} else {
+			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 );
+
+		print "WAIT> press enter"; my $foo = <STDIN>;
 	}
-	warn draw( @trace );
 
+	warn ">>> ended at $pos, line length: $len\n";
+	return $len;
 }
 
-warn "ended at $pos\n";
+my $shapes = '0,0 1,0';
 
+foreach my $start ( split(/\s/,$shapes) ) {
+	my $len = shape( split(/,/,$start) );
+	warn "## $start has $len elements\n";
+}