+ (check-equal? (eval '(f1 3) env1) false "internal definitions")
+ (eval '(define (fib n)
+ (let fib-iter ((a 1)
+ (b 0)
+ (count n))
+ (if (= count 0)
+ b
+ (fib-iter (+ a b) a (- count 1)))))
+ env1)
+ (check-equal? (eval '(fib 10) env1) 55 "named let"))))