혼자 공부하면서 풀어본 것입니다. 틀린게 꽤 많을지도 모르겠습니다. 문제 있는 부분은 알려주시면 고맙겠습니다.
Exercise 1.1. Below is a sequence of expressions. What is the result printed by the interpreter in response to each expression? Assume that the sequence is to be evaluated in the order in which it is presented.
10
(+ 5 3 4)
(- 9 1)
(/ 6 2)
(+ (* 2 4) (- 4 6))
(define a 3)
(define b (+ a 1))
(+ a b (* a b))
(= a b)
(if (and (> b a) (< b (* a b)))
b
a)
(cond ((= a 4) 6)
((= b 4) (+ 6 7 a))
(else 25))
(+ 2 (if (> b a) b a))
(* (cond ((> a b) a)
((< a b) b)
(else -1))
(+ a 1))
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Exercise 1.2. Translate the following expression into prefix form
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Exercise 1.3. Define a procedure that takes three numbers as arguments and returns the sum of the squares of the two larger numbers.
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Exercise 1.4. Observe that our model of evaluation allows for combinations whose operators are compound expressions. Use this observation to describe the behavior of the following procedure:
(define (a-plus-abs-b a b)
((if (> b
0) + -) a b))
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Exercise 1.5. Ben Bitdiddle has invented a test to determine whether the interpreter he is faced with is using applicative-order evaluation or normal-order evaluation. He defines the following two procedures:
(define (p) (p))
(define (test x y)
(if (=
x 0)
0
y))
Then he evaluates the expression
(test
0 (p))
What behavior will Ben observe with
an interpreter that uses
applicative-order evaluation? What behavior will he observe
with an
interpreter that uses normal-order evaluation? Explain your answer.
(Assume that
the evaluation rule for the special form if is
the
same whether the interpreter is using normal or applicative order:
The predicate
expression is evaluated first, and the result
determines whether to evaluate
the consequent
or the alternative expression.)
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