File: util.scm

package info (click to toggle)
scheme48 1.8%2Bdfsg-1%2Bdeb7u1
  • links: PTS, VCS
  • area: main
  • in suites: wheezy
  • size: 14,984 kB
file content (187 lines) | stat: -rw-r--r-- 4,713 bytes parent folder | download | duplicates (4)
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
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
; Copyright (c) 1993-2008 by Richard Kelsey.  See file COPYING.


; Messages
;==========================================================================

(define (bug format-string . args)
  (apply error (list "~?~%  (compiler error)" format-string args)))

(define (user-error format-string . args)
  (apply error (list "~?~%  (source error)" format-string args)))

(define (user-warning format-string . args)
  (apply error (list "~?~%  (source error)" format-string args)))

; Little utilities.
;========================================================================

(define (true  x) #t)
(define (false x) #f)

(define (or-map proc list)
  (do ((list list (cdr list))
       (r '#f (or (proc (car list)) r)))
      ((null? list) r)))

(define (remove-similar-elts pred list)
  (do ((list list (cdr list))
       (res  '()  (if (mem? pred (car list) res)
                      res
                      (cons (car list) res))))
      ((null-list? list)
       res)))

(define (select-from-table pred table)
  (let ((res '()))
    (table-walk (lambda (key entry)
                  (if (pred key entry)
                      (set! res `((,key . ,entry) . ,res))))
                table)
    res))

(define (table->list table)
  (select-from-table (lambda (x y) #t) table))

(define (table->entry-list table)
  (let ((res '()))
    (table-walk (lambda  (key entry)
                  (set! res (cons entry res)))
                table)
    res))

(define (table-push table key val)
  (let ((old (table-ref table key)))
    (table-set! table key (if old
			      (cons val old)
			      (list val)))
    val))

(define (table-pop table key)
  (let ((old (table-ref table key)))
    (table-set! table key (cdr old))
    (car old)))

(define (merge-lists x y)
  (cond ((null? y) x)
        (else (do ((z x (cdr z))
                   (u y (let ((w (car z)))
                          (if (memq? w u) u (cons w u)))))
                  ((null? z) u)))))

(define (vector-every? pred vec)
  (let loop ((i (- (vector-length vec) '1)))
    (cond ((< i '0)
	   '#t)
          ((not (pred (vector-ref vec i)))
	   '#f)
          (else
	   (loop (- i '1))))))

(define (make-ignorable vars)
  (let loop ((vars vars) (res '()))
    (cond ((null? vars)
           `(ignorable . ,res))
          ((atom? vars)
           `(ignorable ,vars . ,res))
          (else
           (loop (cdr vars) (cons (car vars) res))))))

(define (sub-vector->list vec start)
  (do ((i (- (vector-length vec) '1) (- i '1))
       (r '() (cons (vector-ref vec i) r)))
      ((< i start)
       r)))

; A version of ASSQ that works on lists containing atoms.

(define (flag-assq obj list)
  (let loop ((l list))
    (if (null-list? l) 
        #f
        (let ((z (car l)))
          (if (and (pair? z)
                   (eq? obj (car z)))
              z
              (loop (cdr l)))))))

; T system stuff

(define (enforce predicate value)
  (if (predicate value)
      value
      (error "enforce ~A failed on ~A" predicate value)))

(define (writec port char)
  (write-char char port))

(define (mem? predicate object list)
  (let loop ((list list))
    (cond ((null? list)
	   #f)
	  ((predicate object (car list))
	   #t)
	  (else
	   (loop (cdr list))))))

(define (walk-vector procedure vector)
  (do ((i 0 (+ i 1)))
      ((>= i (vector-length vector))
       (values))
    (procedure (vector-ref vector i))))

(define (vector-replace to from count)
  (do ((i 0 (+ i 1)))
      ((>= i count))
    (vector-set! to i (vector-ref from i)))
  (values))

(define (copy-vector vector)
  (let ((new (make-vector (vector-length vector))))
    (do ((i 0 (+ i 1)))
	((= i (vector-length vector)))
      (vector-set! new i (vector-ref vector i)))
    new))

(define (copy-list list)
  (if (null-list? list)
      list
      (let ((copy (cons (car list) '())))
	(let loop ((list (cdr list)) (result copy))
	  (cond ((not (null-list? list))
		 (let ((next (cons (car list) '())))
		   (set-cdr! result next)
		   (loop (cdr list) next)))))
	copy)))

(define (symbol-hash symbol)
  (string-hash (symbol->string symbol)))

(define string-hash (structure-ref features string-hash))

(define (object-hash x)
  0)           ; wah!

(define (union l1 l2)
  (if (null? l2)
      l1
      (do ((l1 l1 (cdr l1))
	   (res l2 (if (memq? (car l1) res) res (cons (car l1) res))))
	  ((null? l1)
	   res))))

(define (intersection l1 l2)
  (if (null? l2)
      '()
      (do ((l1 l1 (cdr l1))
	   (res '() (if (memq? (car l1) l2) (cons (car l1) res) res)))
	  ((null? l1)
	   res))))

(define (set-difference l1 l2)
  (if (null? l2)
      l1
      (do ((l1 l1 (cdr l1))
	   (res '() (if (memq? (car l1) l2) res (cons (car l1) res))))
	  ((null? l1)
	   res))))