c:\@Work\Perl>perl -wMstrict -MData::Dump -le
"my @captures =
   grep defined,
   ':aa2bb4cc6dd8' =~ m{ \G (?<! \A) (\w\w) (\d) | \A (:) }xmsg;
 dd \@captures;
"
[":", "aa", 2, "bb", 4, "cc", 6, "dd", 8]