exit case body/prog/function

[dean]

I'd like to do this but am not sure if it's possible

( case <whatever>
   #========= start of match clause
   (<some match>
       (prog
           (if (<some test is T>) (EXIT THIS MATCH CLAUSE/PROG))
           (otherwise you'll execute this statement)
       )
  )
  #========= end of match clause
  .
  .
  .
I also wonder if there's a similar... (if (T) (EXIT FUNCTION))