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Preface
Part I
Chap 1
Chap 2
Chap 3
XEmacs
Chap 4
Chap 5
Chap 6
Chap 7
Chap 8
Chap 9
Part II
Chap 10
Chap 11
Chap 12
Chap 13
Chap 14
Chap 15
Chap 16
Chap 17
Chap 18
Chap 19
Chap 20
Chap 21
Chap 22
Chap 23
Part III
Chap 24
Chap 25
Chap 26
Chap 27
Chap 28
Chap 29
Chap 30
Chap 31
Chap 32
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CHAPTER 21: MAPPING FUNCTIONS
- Corrections
-
- Page 153, lines 8 - 16: Change the indentation from
(defun scalar-add1 (vector)
"VECTOR is a list of numbers.
Returns a list just like it,
except that each number in it is incremented by 1."
(check-type vector list)
(typecase vector
(null '())
(cons (cons (1+ (first vector))
(scalar-add1 (rest vector))))))
to
(defun scalar-add1 (vector)
"VECTOR is a list of numbers.
Returns a list just like it,
except that each number in it is incremented by 1."
(check-type vector list)
(typecase vector
(null '())
(cons (cons (1+ (first vector))
(scalar-add1 (rest vector))))))
- Page 154, line -8: Change scalar-add1, then, is to
scalar-add1 is.
- Notes
-
- Read Chapter 21. There are three important concepts in this
chapter:
- the function
mapcar;
-
lambda expressions;
- the concept of closures.
- Do Exercises 21.1 - 21.4 as you need to in order to
understand the material.
- Do Exercise 21.5, and then compare your definition to the one in
Appendix A.
- Create and submit a file named
ch21.cl with
code in the ch21 package to define the function
vector-product as described in Exercise 21.8. As the
text says, the product of the column vector
(3)
(4)
represented by the list (3 4) times the row vector
(5 6 7)
represented by the list (5 6 7) is the matrix
(15 18 21)
(20 24 28)
represented by the list ((15 18 21) (20 24 28)).
When this is done by Common Lisp it is
CH21(134): (vector-product '(3 4) '(5 6 7))
((15 18 21) (20 24 28))
Do not use recursion on any list for this exercise. Instead, you will
use mapcar twice. If it's too confusing to have two
mapcars in one function, write
vector-product to make use of scalar-times.
- When you have submitted correct exercises through this
chapter, you will have earned a grade of B-.
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