1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
|
;"sc4opt.scm" Implementation of optional Scheme^4 functions for IEEE Scheme
;Copyright (C) 1991, 1993 Aubrey Jaffer
;
;Permission to copy this software, to modify it, to redistribute it,
;to distribute modified versions, and to use it for any purpose is
;granted, subject to the following restrictions and understandings.
;
;1. Any copy made of this software must include this copyright notice
;in full.
;
;2. I have made no warrantee or representation that the operation of
;this software will be error-free, and I am under no obligation to
;provide any services, by way of maintenance, update, or otherwise.
;
;3. In conjunction with products arising from the use of this
;material, there shall be no use of my name in any advertising,
;promotional, or sales literature without prior written consent in
;each case.
;;; Some of these functions may be already defined in your Scheme.
;;; Comment out those definitions for functions which are already defined.
;;; This code conforms to: William Clinger and Jonathan Rees, editors.
;;; Revised^4 Report on the Algorithmic Language Scheme.
(define (list-tail l p)
(if (< p 1) l (list-tail (cdr l) (- p 1))))
(define (string->list s)
(do ((i (- (string-length s) 1) (- i 1))
(l '() (cons (string-ref s i) l)))
((< i 0) l)))
(define (list->string l) (apply string l))
(define string-copy string-append)
(define (string-fill! s obj)
(do ((i (- (string-length s) 1) (- i 1)))
((< i 0))
(string-set! s i obj)))
(define (list->vector l) (apply vector l))
(define (vector->list s)
(do ((i (- (vector-length s) 1) (- i 1))
(l '() (cons (vector-ref s i) l)))
((< i 0) l)))
(define (vector-fill! s obj)
(do ((i (- (vector-length s) 1) (- i 1)))
((< i 0))
(vector-set! s i obj)))
|
