练习 1.1

将题目给出的表达式一个个输入进解释器里面就可以了:

1 ]=> 10

;Value: 10

1 ]=> (+ 5 3 4)

;Value: 12

1 ]=> (- 9 1)

;Value: 8

1 ]=> (/ 6 2)

;Value: 3

1 ]=> (+ (* 2 4) (- 4 6))

;Value: 6

1 ]=> (define a 3)

;Value: a

1 ]=> (define b (+ a 1))

;Value: b

1 ]=> (+ a b (* a b))

;Value: 19

1 ]=> (= a b)

;Value: #f

1 ]=> (if (and (> b a) (< b (* a b)))
          b
          a)

;Value: 4

1 ]=> (cond ((= a 4) 6)
            ((= b 4) (+ 6 7 a))
            (else 25))

;Value: 16

1 ]=> (+ 2 (if (> b a) b a))

;Value: 6

1 ]=> (* (cond ((> a b) a)
               ((< a b) b)
               (else -1))
         (+ a 1))

;Value: 16

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