Avoiding recomputation or recapitulation: (g x x)

[SHRAGE at WHARTON-10 (Jeffrey Shrager)]

How about a macro, WHERE, that had a form something like:

	(where ((x e1) (y e2) ...)
	       expr)

==>	((lambda (x y ...) expr) e1 e2 ...)

Then one could say : (where ( (x 5) (y 6) ) (+ x x (/ y x)) )  [or something
like that].  No need for locals beyond the scope of the expression, no need
for fifo register description, self-cleaning (via lambda), etc.   You still
have to give the args names but they are cleanly localized by lambda.