Condensed Tags

What we need here is a more efficient way to write complicated tags.
Consider: [b][u][i][o] could be halved in length by supporting a [buio] tag. This is analogous to CADR or somesuch, which is obviously wonderful. Only single-letter tags would be usable this way.

even better
(post
  (name "MrSatori")
  (email "sage")
  (body
    ("We need more "
      (b (sup "B")
         (sub "b")
         "code")
       " on "
      (spoiler "/prog/"))))