$ perl -le'
my $x = q[-----MMMMM------IIIII----MMM---OOOO---I---MMMM-----];

while ( $x =~ /([^-])/g ) {
    my $y = $1;
    pos( $x )--;
    $x =~ /\G$y+/g and print $-[0] + 1, $-[0] + 1 == $+[0] ? "" : "-$+
+[0]", ":$y";
    }
'
6-10:M
17-21:I
26-28:M
32-35:O
39:I
43-46:M
[download]