while ($string =~ /([CSH][CSHL]*[CSH])/g) {
    print "$1, ";
}

##</code><code>##

print join ', ', $string =~ /([CSH][CSHL]*[CSH])/g;

##</code><code>##

for ($string) {
   s/-L+|L+-/-/g;
   s/^L+//;
   s/L+$//;
   print join ', ', /([CSHL]{2,})/g;
}