I was writing the section on tail recursion in the OCaml tutorial, and
was surprised to find out that the range function (below) isn't tail
recursive. Or at least it causes a stack overflow on a
large-but-not-unreasonable input value.

let rec range a b =
  if a > b then []
  else a :: range (a+1) b
  ;;

let list = range 1 1000000;;

Printf.printf "length = %d\n" (List.length list);;

Can you tell me why this function isn't tail recursive, and share any
useful tips on how to tell whether a function is or is not tail
recursive?

Thanks,

Rich.

-- 
Richard Jones, Red Hat Inc. (London) and Merjis Ltd. http://www.merjis.com/
http://www.annexia.org/ Freshmeat projects: http://freshmeat.net/users/rwmj
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