Re: the necessity of Lisp's Objects?

rem642b@[EMAIL PROTECTED]
 (Robert Maas, see http://tinyurl.com/uh3t)
writes:
> [...]
>> tail recursion
>
> This is not as useful as it's hyped up to be. Sure if you write a
> factorial recursively to emulate iteration, a compiler can convert
> it back to the equivalent iterative algorithm to avoid stack
> overflow. Whooptie-doo. True recursion isn't tail recursion in the
> first place so you don't need this case handled specially. For
> example, the right way to compute factorial recursively is:
> 
> (defun prod (m n)
>   (if (< (+ m 1) n)
>       (let ((mid (floor (+ m n) 2)))
>         (* (prod m mid) (prod mid n)))
>       m))
> (defun fact (n) (prod 1 (+ 1 n)))
>
> The whole point of recursion is divide-and-conquer, epecially if
> you have multiple processors which can run in parallel on sub-tasks.
> Always spawing one sub-task to do a trivial case and the other
> sub-task to do all the work except that one trivial case, whereby
> you actually compute the trivial case directly and tail-recurse on
> the all-the-rest, is outright stupid.

Very good!

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