c:\@Work\Perl\monks>perl -wMstrict -le
"my $s = 'foo--bar--baz';
 ;;
 while ($s =~ m{ (\w+) }xmsg) {
   printf qq{matched '$1' %s of '$s' \n},
     $-[1] == 0         ? 'at start'  :
     $+[1] == length $s ? 'at very end' :
                          'in middle';
   }
"
matched 'foo' at start of 'foo--bar--baz'
matched 'bar' in middle of 'foo--bar--baz'
matched 'baz' at very end of 'foo--bar--baz'