macros expanding into definitions

["Aubrey Jaffer" <jaffer@martigny.ai.mit.edu>]

   Date: Wed, 2 Dec 92 14:51:08 -0500
   From: "Guillermo J. Rozas" <gjr@martigny.ai.mit.edu>
   Reply-To: gjr@martigny.ai.mit.edu

      Date: Wed, 2 Dec 92 14:03:15 -0500
      From: "Mark Friedman" <markf@martigny.ai.mit.edu>
      Reply-To: markf@martigny.ai.mit.edu

      The initial (and I thought primary) motivation for all this was to
      make internal defines consistent with top-level defines. The above
      rules do not do this. For example, the above disallows:

	(define x 0)
	(define (foo)
	  (set! x 1)
	  (define x 2))
	(foo)
	x

   It is not disallowed, it rewrites into

   (define x 0)
   (define (foo)
     (let ((x))
       (set! x 1)
       (set! x 2)))
   (foo)
   x

...

   In other words, the nice property of the new proposal is that if you
   have a program that works, you can wrap it in

   (let ()
     <program>
     )

   and it still works the same way modulo assignments without definitions
   of the names of the standard procedures (CAR, WRITE, etc.), although
   if I remember correctly IEEE states that this is an error.

This is a very nice property.  Compatible with your property, I would
still prefer that (if a variable is DEFINEd) a DEFINE of a variable be
required to precede SET!s of that variable.  This is currently
required both at top level and internally.  I think most beginners are
used to defining variables before use; so this would eliminate one
source of confusion about scope as illustrated above.