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Preface
Part I
Chap 1
Chap 2
Chap 3
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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 26: SEQUENCES
- Corrections
- Page 304, lines 13 - 28: Change
(defun substitute (pat subs)
"Returns a tree like PAT,
but with every variable that is bound in
the substitution SUBS
replaced by the term it is bound to."
(check-type subs list)
(cond ((atom pat)
(if (and (variablep pat) (boundp pat subs))
(bound-to pat subs)
pat))
((and (svariablep (first pat))
(boundp (first pat) subs))
(append (bound-to (first pat) subs)
(substitute (rest pat) subs)))
(t (cons (substitute (first pat) subs)
(substitute (rest pat) subs)))))
to
(defun substitute (pat subs)
"Returns a tree like PAT,
but with every variable that is bound in
the substitution SUBS
replaced by the term it is bound to."
;; pat cannot be a sequence variable because there might be no
;; environment to splice its value into.
(check-type pat (not (satisfies svariablep)))
(check-type subs list)
(cond ((atom pat)
(if (and (variablep pat) (boundp pat subs))
(bound-to pat subs)
pat))
((svariablep (first pat))
(if (boundp (first pat) subs)
(append (bound-to (first pat) subs)
(substitute (rest pat) subs))
(cons (first pat) (substitute (rest pat) subs))))
(t (cons (substitute (first pat) subs)
(substitute (rest
pat) subs)))))
- Notes
-
- Read Chapter 26.
- Do Exercises 26.1 - 26.4 as you need to in order to
understand the material. Notice that the answer to 26.4 is given in
Appendix A.
- You may want to review the dvi
or PostScript
version of the overview and specification of Project P1.
- Do Exercises 26.8, 26.9, 26.12, 26.13, and 26.14. Note that,
as part of Exercise 26.14, you should redefine the
*grammar-rules* parameter to be the set of rules shown on
page 195. Submit your updated version of match.cl
- Do Exercises 26.10 and 26.11, but you needn't submit anything
for them.
- When you have submitted correct exercises through this
chapter, you will have earned a grade of B+.
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