exitlist in new-style DO

[Alan Bawden <ALAN at MIT-MC>]

    Date: 21 February 1981 1540-EST
    From: Paul.Hilfinger at CMU-10A

    Is there some deep underlying reason why in the expression
    
	    (do ( ... ) (e1)  ... )
    
    MacLisp does not treat e1 as thelast element in the EXITLIST and returns
    (instead) NIL?  Grumble.

My understanding has always been that it works this way so that:

	(do var init step stop body)

and

	(do ((var init step)) (stop) body)

will do exactly the same thing.

Of course you could write "(stop nil)" if that is what you really
wanted, right?  If we are going to consider changing the behavior of
DO, perhaps we should consider removing this wierd case:

	(do ( ... ) nil ... )

How many of you even know about the wierd thing that this is defined to
do?