defun semantics

[Earl A. Killian <EAK at MIT-MC>]

Does defun add the function name to the lexical environment of
the body?  Should it?

For example, in

(defun revappend (a b)
  (if (null a)
      b
      (revappend (cdr a) (cons (car a) b))))

is the tail recursion implementable as a simple GO, or must the
system consult the function cell of the symbol REVAPPEND?  I vote
for allowing the GO, i.e. adding REVAPPEND to the lexical
function environment, in effect, defining DEFUN in terms of
LABELS instead of LAMBDA.