Tail Recursion in Common Lisp ???

[Daniel L. Weinreb <DLW@QUABBIN.SCRC.Symbolics.COM>]

Since the question of tail recursion comes up again and again, though, I
think the spec ought to make some explicit mention of the policy of the
language definition.  The statement should indicate that if you write a
program that recurses heavily, thinking that this is not consuming stack
space due to tail recursion, you should be aware that not all
implementations have this property and your program might not work.
Yes, I agree that there are a million issues like this and we can't
mention them all explicitly.  In this case, though, it's worth a
specific mention just because experience shows that many people wonder
about it and ask (presumably because the presence of lexical scoping
suggests other similarities with Scheme).