till (
  - /match0/ => \&doOtherProcessing,
  - /match1/ => \&doStage1,
  - /match2/ => \&doStage2,
  - /match3/ => \&doStage3,
)

##</code><code>##

till (
  - /match0/ => sub { print "default Processing" },
  - yadda yadda ...
)