Re: tail recursion (was Re: a (revised) draft of R5RS)

[Richard Kelsey <kelsey@research.nj.nec.com>]

   Cc: rrrs-authors@martigny.ai.mit.edu
   References: <ogtzpthjj8r.fsf@laozi.mitre.org>
   Date: Tue, 27 May 1997 09:38:10 -0400
   From: Matthias Blume <blume@CS.Princeton.EDU>

   [ ... much elided ...]

   Especially the higher-order variety of built-in primitives is
   troublesome:

   - Is the call to f in (for-each (lambda (x) (if x (f x) 0)) '(#f 1)) a
     tail-call?

The value returned by FOR-EACH is currently explicitly unspecified,
which would imply that FOR-EACH is never required to use a tail-call
when calling its procedure argument.  Thus the call to F may or may
not be a tail call.
                                        -Richard