Avoiding Variable Capture with Scope

(defmacro sum-squares-w (x y)

`(let* ((x0 ,x) ; WRONG (X0 captured)

(y0 ,y) ; problem occurs in this line

(x2 (* x0 x0)) ;; if form y refers

(y2 (* y0 y0))) ;; to x0

(+ x2 y2)))

(defmacro sum-squares-r (x y)

`(let ((x0 ,x) ; RIGHT

(y0 ,y))

(let ((x2 (* x0 x0))

(y2 (* y0 y0)))

(+ x2 y2))))

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