* 2 FETCH (UID 2 FLAGS (\Answered \Seen) INTERNALDATE "05-Jun-2008 07:19:01 +1000" RFC822.SIZE 5144 BODYSTRUCTURE ("text" "plain" ("charset" "ISO-8859-1") NIL NIL "7bit" 2053 46 NIL ("inline" NIL) NIL NIL))

##</code><code>##

  "UID"           => "2",
  "FLAGS"         => "\Answered \Seen",
  "INTERNALDATE"  => "05-Jun-2008 07:19:01 +1000",
  "RFC822.SIZE"   => "5144",
  "BODYSTRUCTURE" => "text" "plain" ("charset" "ISO-8859-1") NIL NIL "7bit" 2053 46 NIL ("inline" NIL) NIL NIL",

##</code><code>##

  (?:
    (?{ local $d=0 }) # set depth to 0
    (                 # start capture
      (?:                  
        \(            # opening paren
        (?{$d++})     # increment the depth
        |  
        \)            # or closing paren
        (?{$d--})     # decrement the depth
        (?(?{$d==0})  # if we're back to the start
          (*ACCEPT)   # we're done
        )
        |
        (?>[^()]*)    # or there's just some normal text
      )*
      (?(?{$d!=0})    # done. did we reach a matching closing paren
        (?!)          # nope, failed
      )
    )                 # end capture
  )