[W/K] :: tail recursion

  tail recursion n. If you aren't sick of it already, see tail
     recursion.
  
  

  tail recursion
       
           When the last thing a function (or procedure)
          does is to call itself.  Such a function is called tail
          recursive.  A function may make several recursive calls but a
          call is only tail-recursive if the caller returns immediately
          after it.  E.g.
       
          	f n = if n < 2 then 1 else f (f (n-2) + 1)
       
          Here the both calls to fib are recursive but only the outer
          one is tail recursive.
       
          See tail recursion optimisation, and, if you aren't sick of
          them already, recursion, tail recursion.
       
          [{Jargon File]
       
          (1996-02-22)