This file is indexed.

/usr/share/slib/scanf.scm is in slib 3b1-5.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  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
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
;;;;"scanf.scm" implemenation of formatted input
;Copyright (C) 1996, 1997, 2003 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 warranty 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.

;;; Originally jjb@isye.gatech.edu (John Bartholdi) wrote some public
;;; domain code for a subset of scanf, but it was too difficult to
;;; extend to POSIX pattern compliance.  Jan 96, I rewrote the scanf
;;; functions starting from the POSIX man pages.

(require 'string-port)
(require 'rev2-procedures)
(require 'rev4-optional-procedures)

(define (stdio:scan-and-set format-string input-port . args)
  (define setters (if (equal? '(#f) args) #f args))
  (define assigned-count 0)
  (define chars-scanned 0)
  (define items '())
  (define (return)
    (cond ((and (zero? chars-scanned)
		(eof-object? (peek-char input-port)))
	   (peek-char input-port))
	  (setters assigned-count)
	  (else (reverse items))))
  (cond
   ((equal? "" format-string) (return))
   ((string? input-port)
    (call-with-input-string
	input-port
      (lambda (str-port)
	(apply stdio:scan-and-set format-string str-port args))))
   (else
    (call-with-input-string
	format-string
      (lambda (format-port)

	(define (char-non-numeric? c) (not (char-numeric? c)))

	(define (flush-whitespace port)
	  (do ((c (peek-char port) (peek-char port))
	       (i 0 (+ 1 i)))
	      ((or (eof-object? c) (not (char-whitespace? c))) i)
	    (read-char port)))

	(define (flush-whitespace-input)
	  (set! chars-scanned (+ (flush-whitespace input-port) chars-scanned)))

	(define (read-input-char)
	  (set! chars-scanned (+ 1 chars-scanned))
	  (read-char input-port))

	(define (add-item report-field? next-item)
	  (cond (setters
		 (cond ((and report-field? (null? setters))
			(slib:error 'scanf "not enough variables for format"
				    format-string))
		       ((not next-item) (return))
		       ((not report-field?) (loop1))
		       (else
			(let ((suc ((car setters) next-item)))
			  (cond ((not (boolean? suc))
				 (slib:warn 'scanf "setter returned non-boolean"
					    suc)))
			  (set! setters (cdr setters))
			  (cond ((not suc) (return))
				((eqv? -1 report-field?) (loop1))
				(else
				 (set! assigned-count (+ 1 assigned-count))
				 (loop1)))))))
		((not next-item) (return))
		(report-field? (set! items (cons next-item items))
			       (loop1))
		(else (loop1))))

	(define (read-string width separator?)
	  (cond (width
		 (let ((str (make-string width)))
		   (do ((i 0 (+ 1 i)))
		       ((>= i width)
			str)
		     (let ((c (peek-char input-port)))
		       (cond ((eof-object? c)
			      (set! str (substring str 0 i))
			      (set! i width))
			     ((separator? c)
			      (set! str (if (zero? i) "" (substring str 0 i)))
			      (set! i width))
			     (else
			      (string-set! str i (read-input-char))))))))
		(else
		 (do ((c (peek-char input-port) (peek-char input-port))
		      (l '() (cons c l)))
		     ((or (eof-object? c) (separator? c))
		      (list->string (reverse l)))
		   (read-input-char)))))

	(define (read-word width separator?)
	  (let ((l (read-string width separator?)))
	    (if (zero? (string-length l)) #f l)))

	(define (loop1)
	  (define fc (read-char format-port))
	  (cond
	   ((eof-object? fc)
	    (return))
	   ((char-whitespace? fc)
	    (flush-whitespace format-port)
	    (flush-whitespace-input)
	    (loop1))
	   ((eqv? #\% fc)		; interpret next format
	    (set! fc (read-char format-port))
	    (let ((report-field? (not (eqv? #\* fc)))
		  (width #f))

	      (define (width--) (if width (set! width (+ -1 width))))

	      (define (read-u)
		(string->number (read-string width char-non-numeric?)))

	      (define (read-o)
		(string->number
		 (read-string
		  width
		  (lambda (c)
		    (not (memv c '(#\0 #\1 #\2 #\3 #\4 #\5 #\6 #\7)))))
		 8))

	      (define (read-x)
		(string->number
		 (read-string
		  width
		  (lambda (c) (not (memv (char-downcase c)
					 '(#\0 #\1 #\2 #\3 #\4 #\5 #\6 #\7 #\8
					   #\9 #\a #\b #\c #\d #\e #\f)))))
		 16))

	      (define (read-radixed-unsigned)
		(let ((c (peek-char input-port)))
		  (case c
		    ((#\0) (read-input-char) (width--)
		     (set! c (peek-char input-port))
		     (case c
		       ((#\x #\X) (read-input-char) (width--) (read-x))
		       (else (read-o))))
		    (else (read-u)))))

	      (define (read-ui)
		(let* ((dot? #f)
		       (mantissa
			(read-word
			 width
			 (lambda (c)
			   (not (or (char-numeric? c)
				    (cond (dot? #f)
					  ((eqv? #\. c) (set! dot? #t) #t)
					  (else #f)))))))
		       (exponent
			(cond
			 ((not mantissa) #f)
			 ((and (or (not width) (> width 1))
			       (memv (peek-char input-port) '(#\E #\e)))
			  (read-input-char)
			  (width--)
			  (let* ((expsign
				  (case (peek-char input-port)
				    ((#\-) (read-input-char)
				     (width--) "-")
				    ((#\+) (read-input-char)
				     (width--) "+")
				    (else "")))
				 (expint
				  (and (or (not width) (positive? width))
				       (read-word width char-non-numeric?))))
			    (and expint (string-append "e" expsign expint))))
			 (else #f))))
		  (and mantissa
		       (string->number
			(string-append
			 "#i" (or mantissa "") (or exponent ""))))))

	      (define (read-signed proc)
		(case (peek-char input-port)
		  ((#\-) (read-input-char) (width--)
		   (let ((ret (proc))) (and ret (- ret))))
		  ((#\+) (read-input-char) (width--) (proc))
		  (else (proc))))

	      ;;(trace read-word read-signed read-ui read-radixed-unsigned read-x read-o read-u)

	      (cond ((not report-field?) (set! fc (read-char format-port))))
	      (if (char-numeric? fc) (set! width 0))
	      (do () ((or (eof-object? fc) (char-non-numeric? fc)))
		(set! width (+ (* 10 width) (string->number (string fc))))
		(set! fc (read-char format-port)))
	      (case fc			;ignore h,l,L modifiers.
		((#\h #\l #\L) (set! fc (read-char format-port))))
	      (case fc
		((#\n) (if (not report-field?)
			   (slib:error 'scanf "not saving %n??"))
		 (add-item -1 chars-scanned)) ;-1 is special flag.
		((#\c #\C)
		 (if (not width) (set! width 1))
		 (let ((str (make-string width)))
		   (do ((i 0 (+ 1 i))
			(c (peek-char input-port) (peek-char input-port)))
		       ((or (>= i width)
			    (eof-object? c))
			(add-item report-field? (substring str 0 i)))
		     (string-set! str i (read-input-char)))))
		((#\s #\S)
		 ;;(flush-whitespace-input)
		 (add-item report-field? (read-word width char-whitespace?)))
		((#\[)
		 (set! fc (read-char format-port))
		 (let ((allbut #f))
		   (case fc
		     ((#\^) (set! allbut #t)
		      (set! fc (read-char format-port))))

		   (let scanloop ((scanset (list fc)))
		     (set! fc (read-char format-port))
		     (case fc
		       ((#\-)
			(set! fc (peek-char format-port))
			(cond
			 ((and (char<? (car scanset) fc)
			       (not (eqv? #\] fc)))
			  (set! fc (char->integer fc))
			  (do ((i (char->integer (car scanset)) (+ 1 i)))
			      ((> i fc) (scanloop scanset))
			    (set! scanset (cons (integer->char i) scanset))))
			 (else (scanloop (cons #\- scanset)))))
		       ((#\])
			(add-item report-field?
				  (read-word
				   width
				   (if allbut (lambda (c) (memv c scanset))
				       (lambda (c) (not (memv c scanset)))))))
		       (else (cond
			      ((eof-object? fc)
			       (slib:error 'scanf "unmatched [ in format"))
			      (else (scanloop (cons fc scanset)))))))))
		((#\o #\O)
		 ;;(flush-whitespace-input)
		 (add-item report-field? (read-o)))
		((#\u #\U)
		 ;;(flush-whitespace-input)
		 (add-item report-field? (read-u)))
		((#\d #\D)
		 ;;(flush-whitespace-input)
		 (add-item report-field? (read-signed read-u)))
		((#\x #\X)
		 ;;(flush-whitespace-input)
		 (add-item report-field? (read-x)))
		((#\e #\E #\f #\F #\g #\G)
		 ;;(flush-whitespace-input)
		 (add-item report-field? (read-signed read-ui)))
		((#\i)
		 ;;(flush-whitespace-input)
		 (add-item report-field? (read-signed read-radixed-unsigned)))
		((#\%)
		 (cond ((or width (not report-field?))
			(slib:error 'SCANF "%% has modifiers?"))
		       ((eqv? #\% (read-input-char))
			(loop1))
		       (else (return))))
		(else (slib:error 'SCANF
				  "Unknown format directive:" fc)))))
	   ((eqv? (peek-char input-port) fc)
	    (read-input-char)
	    (loop1))
	   (else (return))))
	;;(trace flush-whitespace-input flush-whitespace add-item return read-string read-word loop1)
	(loop1))))))

;;;This implements a Scheme-oriented version of SCANF: returns a list of
;;;objects read (rather than set!-ing values).
;@
(define (scanf-read-list format-string . optarg)
  (define input-port
    (cond ((null? optarg) (current-input-port))
	  ((not (null? (cdr optarg)))
	   (slib:error 'scanf-read-list 'wrong-number-of-args optarg))
	  (else (car optarg))))
  (cond ((input-port? input-port)
	 (stdio:scan-and-set format-string input-port #f))
	((string? input-port)
	 (call-with-input-string
	     input-port (lambda (input-port)
			  (stdio:scan-and-set format-string input-port #f))))
	(else (slib:error 'scanf-read-list "argument 2 not a port"
			  input-port))))

(define (stdio:setter-procedure sexp)
  (let ((v (gentemp)))
    (cond ((symbol? sexp) `(lambda (,v) (set! ,sexp ,v) #t))
	  ((not (and (pair? sexp) (list? sexp)))
	   (slib:error 'scanf "setter expression not understood" sexp))
	  (else
	   (case (car sexp)
	     ((vector-ref) `(lambda (,v) (vector-set! ,@(cdr sexp) ,v) #t))
	     ((substring)
	      `(lambda (,v) (substring-move-left!
			     ,v 0 (min (string-length ,v)
				       (- ,(cadddr sexp) ,(caddr sexp)))
			     ,(cadr sexp) ,(caddr sexp))
		       #t))
	     ((list-ref)
	      `(lambda (,v) (set-car! (list-tail ,@(cdr sexp)) ,v) #t))
	     ((car) `(lambda (,v) (set-car! ,@(cdr sexp) ,v) #t))
	     ((cdr) `(lambda (,v) (set-cdr! ,@(cdr sexp) ,v) #t))
	     (else (slib:error 'scanf "setter not known" sexp)))))))

;@
(defmacro scanf (format-string . args)
  `(stdio:scan-and-set ,format-string (current-input-port)
		       ,@(map stdio:setter-procedure args)))
;@
(defmacro sscanf (str format-string . args)
  `(stdio:scan-and-set ,format-string ,str
		       ,@(map stdio:setter-procedure args)))
;@
(defmacro fscanf (input-port format-string . args)
  `(stdio:scan-and-set ,format-string ,input-port
		       ,@(map stdio:setter-procedure args)))