blob: a7f2305a505b4bd5839f2e2889f3f14b7ce1a65f (
plain)
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
|
;;;; Scheme Regular Expression Language Implementation -- regexp.scm
(define (r:dot) ".")
(define (r:bol) "^")
(define (r:eol) "$")
(define (r:quote string)
(r:seq
(call-with-output-string ; see RefMan section 14.3
(lambda (port)
(let ((end (string-length string)))
(do ((i 0 (+ i 1))) ((not (< i end))) ; see RefMan 2.9
(let ((c (string-ref string i)))
(if (or (char=? c #\.)
(char=? c #\[)
(char=? c #\\)
(char=? c #\^)
(char=? c #\$)
(char=? c #\*))
(write-char #\\ port))
(write-char c port))))))))
(define (r:char-from char-set) ; see RefMan section 5.6
(let ((members (char-set-members char-set)))
(cond ((not (pair? members))
(r:seq))
((not (pair? (cdr members)))
(r:quote (string (car members))))
(else
(%char-from #f members)))))
(define (r:char-not-from char-set)
(%char-from #t (char-set-members char-set)))
(define (%char-from negate? members)
(let ((right? (memv #\] members))
(caret? (memv #\^ members))
(hyphen? (memv #\- members))
(others
(delete-matching-items members
(lambda (c)
(or (char=? c #\])
(char=? c #\^)
(char=? c #\-))))))
(if (and caret?
hyphen?
(not right?)
(not negate?)
(null? others))
"[-^]"
(string-append "["
(if negate? "^" "")
(if right? "]" "")
(list->string others)
(if caret? "^" "")
(if hyphen? "-" "")
"]"))))
;;; Means of combination for patterns
(define (r:seq . exprs)
(string-append "\\(" (apply string-append exprs) "\\)"))
(define (r:alt . exprs)
(if (pair? exprs)
(apply r:seq
(cons (car exprs)
(append-map (lambda (expr)
(list "\\|" expr))
(cdr exprs))))
(r:seq)))
(define (r:repeat min max expr)
(if (not (exact-nonnegative-integer? min))
(error "Min must be non-negative integer:" min))
(if max
(begin
(if (not (exact-nonnegative-integer? max))
(error "Max must be non-negative integer:" max))
(if (not (<= min max))
(error "Min not less than max:" min max))))
(cond ((not max)
(apply r:seq
(append (make-list min expr)
(list expr "*"))))
((= max min)
(apply r:seq (make-list min expr)))
(else
(apply r:seq
(append (make-list min expr)
(make-list (- max min)
(r:seq expr "\\|")))))))
;;; The following magic allows a program in MIT/GNU Scheme to call the
;;; grep system utility, returning the list of grep output lines to
;;; the caller. You can make similar mechanisms to call other system
;;; utilities.
(load-option 'synchronous-subprocess)
(define (r:grep expr filename)
(r:grep-like "grep" '() expr filename))
(define (r:egrep expr filename)
(if (eq? microcode-id/operating-system 'nt)
(r:grep-like "grep" '("-E") expr filename)
(r:grep-like "egrep" '() expr filename)))
(define (r:grep-like program options expr filename)
(let ((port (open-output-string)))
(and (= (run-synchronous-subprocess program
(append options
(list "-e" expr (->namestring filename)))
'output port)
0)
(r:split-lines (get-output-string port)))))
(define (r:split-lines string)
(reverse
(let ((end (string-length string)))
(let loop ((i 0) (lines '()))
(if (< i end)
(let ((j
(substring-find-next-char string i end #\newline)))
(if j
(loop (+ j 1)
(cons (substring string i j) lines))
(cons (substring string i end) lines)))
lines)))))
#|
;;; An alternate implementation using MIT/GNU Scheme's internal
;;; regular-expression interpreter.
(define (r:grep expr filename)
(call-with-input-file filename
(lambda (port)
(let loop ((lines '()))
(let ((line (read-line port)))
(if (eof-object? line)
(reverse lines)
(loop (if (re-string-search-forward expr line #f)
(cons line lines)
lines))))))))
|#
#|
;;; For example...
;;; Note, the result of the next two requests were not in this file
;;; when the requests were made!
(pp (r:grep (r:quote "r:sex") "regexp.scm"))
("(pp (r:grep (r:quote \"r:sex\") \"regexp.scm\"))")
;Unspecified return value
(pp (r:grep (r:quote "r:seq") "regexp.scm"))
(" (r:seq"
"\t (r:seq))"
"(define (r:seq . exprs)"
" (apply r:seq"
" (r:seq)))"
"\t (apply r:seq"
"\t (apply r:seq (make-list min expr)))"
"\t (apply r:seq"
"\t\t\t\t (r:seq expr \"\\\\|\")))))))"
"(pp (r:grep (r:quote \"r:seq\") \"regexp.scm\"))"
"(pp (r:grep (r:seq (r:quote \"a\") (r:dot) (r:quote \"c\")) \"tests.txt\"))"
" (r:grep (r:seq \" \""
" (r:seq (r:bol)")
;Unspecified return value
(pp (r:grep (r:seq (r:quote "a") (r:dot) (r:quote "c")) "tests.txt"))
("[00]. abc"
"[01]. aac"
"[02]. acc"
"[03]. zzzaxcqqq"
"[10]. catcatdogdog"
"[12]. catcatcatdogdogdog")
;Unspecified return value
;;; And...
(pp (r:grep (r:alt (r:quote "foo") (r:quote "bar") (r:quote "baz"))
"tests.txt"))
("[05]. foo" "[06]. bar" "[07]. foo bar baz quux")
;Unspecified return value
(pp (r:grep (r:repeat 3 5 (r:alt (r:quote "cat") (r:quote "dog")))
"tests.txt"))
("[09]. catdogcat"
"[10]. catcatdogdog"
"[11]. dogdogcatdogdog"
"[12]. catcatcatdogdogdog"
"[13]. acatdogdogcats"
"[14]. ifacatdogdogs"
"[15]. acatdogdogsme")
;Unspecified return value
(pp
(r:grep (r:seq " "
(r:repeat 3 5 (r:alt (r:quote "cat") (r:quote "dog")))
(r:eol))
"tests.txt"))
("[09]. catdogcat" "[10]. catcatdogdog" "[11]. dogdogcatdogdog")
;Unspecified return value
(pp
(r:grep
(let ((digit
(r:char-from (string->char-set "0123456789"))))
(r:seq (r:bol)
(r:quote "[")
digit
digit
(r:quote "]")
(r:quote ".")
(r:quote " ")
(r:char-from (char-set #\a #\b))
(r:repeat 3 5 (r:alt "cat" "dog"))
(r:char-not-from (char-set #\d #\e #\f))
(r:eol)))
"tests.txt"))
("[13]. acatdogdogcats")
;Unspecified return value
|#
|
