1 (define (make-table key-same?
)
2 (let ((local-table (list
'*table*)))
3
4
5 (define (assoc key records)
6 (cond ((
null?
records) #f)
7 ((key-same?
(caar records) key) (car records))
8 (
else (assoc key (cdr records)))))
9
10 (define (lookup key-
1 key-
2)
11 (let ((subtable (assoc key-
1 (cdr local-
table))))
12 (
if subtable
13 (let ((record (assoc key-
2 (cdr subtable))))
14 (
if record
15 (cdr record)
16 false))
17 false)))
18
19 (define (insert! key-
1 key-
2 value)
20 (let ((subtable (assoc key-
1 (cdr local-
table))))
21 (
if subtable
22 (let ((record (assoc key-
2 (cdr subtable))))
23 (
if record
24 (
set-cdr!
record value)
25 (
set-cdr! subtable (cons (cons key-
2 value)
26 (cdr subtable)))))
27 (
set-cdr! local-
table
28 (cons (list key-
1 (cons key-
2 value))
29 (cdr local-
table)))))
30 'ok)
31
32 (define (dispatch m)
33 (cond ((eq? m
'lookup-proc) lookup)
34 ((eq? m
'insert-proc!) insert!)
35 (
else (error
"Unknow operation --TABLE" m))))
36
37 dispatch))
这一题没什么难点。
转载于:https://www.cnblogs.com/tclan126/p/6815445.html
相关资源：数据结构—成绩单生成器
