Input Box for the Scheme interpreter from Chapter 20

(define leftmost (lambda (l) (letcc skip (lm l skip)))) (define lm (lambda (l out) (cond ((null? l) (quote ())) ((atom? (car l)) (out (car l))) (else ((lambda (x) (lm (car l) out) (lm (cdr l) out)) 0))))) (leftmost (quote (((a)) b (c))))

Output Box

It comes out here.