.
original commit: 17d67f89384f5aa860517430e5191e3ee8a25859
This commit is contained in:
Matthew Flatt
parent
5b8648c52e
commit
d31d9ce2cc
674
collects/mzlib/pregexp.ss
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674
collects/mzlib/pregexp.ss
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(module pregexp mzscheme
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(provide
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pregexp
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pregexp-match-positions
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pregexp-match
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pregexp-split
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pregexp-replace
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pregexp-replace*
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)
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;pregexp.scm
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;Portable regular expressions for Scheme
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;Dorai Sitaram
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;http://www.ccs.neu.edu/~dorai
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;ds26 AT gte.com
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;Oct 2, 1999
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(define *pregexp-comment-char* #\;)
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(define *pregexp-space-sensitive?* #t)
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;The comments ;( and ;) are there only to
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;match escaped parens so my text editor will
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;paren-balance correctly
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(define pregexp-read-pattern
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(lambda (s i n)
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(if (>= i n)
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(list
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(list ':or (list ':seq)) i)
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(let loop ((branches '()) (i i))
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(if (or (>= i n)
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(char=? (string-ref s i) ;(
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#\)))
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(list (cons ':or (reverse! branches)) i)
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(let ((vv (pregexp-read-branch
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s
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(if (char=? (string-ref s i) #\|) (+ i 1) i) n)))
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(loop (cons (car vv) branches) (cadr vv))))))))
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(define pregexp-read-branch
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(lambda (s i n)
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(let loop ((pieces '()) (i i))
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(cond ((>= i n)
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(list (cons ':seq (reverse! pieces)) i))
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((let ((c (string-ref s i)))
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(or (char=? c #\|) ;(
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(char=? c #\))))
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(list (cons ':seq (reverse! pieces)) i))
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(else (let ((vv (pregexp-read-piece s i n)))
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(loop (cons (car vv) pieces) (cadr vv))))))))
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(define pregexp-read-piece
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(lambda (s i n)
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(let ((c (string-ref s i)))
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(case c
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((#\^) (list ':bos (+ i 1)))
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((#\$) (list ':eos (+ i 1)))
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((#\.) (pregexp-wrap-quantifier-if-any
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(list ':any (+ i 1)) s n))
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((#\[) (pregexp-wrap-quantifier-if-any
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(case (string-ref s (+ i 1))
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((#\^)
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(let ((vv (pregexp-read-char-list s (+ i 2) n)))
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(list (list ':neg-char (car vv)) (cadr vv))))
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(else (pregexp-read-char-list s (+ i 1) n)))
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s n))
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((#\() ;)
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(pregexp-wrap-quantifier-if-any
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(pregexp-read-subpattern s (+ i 1) n) s n))
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((#\\)
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(pregexp-wrap-quantifier-if-any
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(cond ((pregexp-read-escaped-number s i n) =>
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(lambda (num-i)
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(list (list ':backref (car num-i)) (cadr num-i))))
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((pregexp-read-escaped-char s i n) =>
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(lambda (char-i)
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(list (car char-i) (cadr char-i))))
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(else (error 'pregexp-read-piece "backslash")))
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s n))
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(else
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(if (or *pregexp-space-sensitive?*
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(and (not (char-whitespace? c))
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(not (char=? c *pregexp-comment-char*))))
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(pregexp-wrap-quantifier-if-any
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(list c (+ i 1)) s n)
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(let loop ((i i) (in-comment? #f))
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(if (>= i n) (list ':empty i)
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(let ((c (string-ref s i)))
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(cond (in-comment?
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(loop (+ i 1)
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(not (char=? c #\newline))))
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((char-whitespace? c)
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(loop (+ i 1) #f))
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((char=? c *pregexp-comment-char*)
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(loop (+ i 1) #t))
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(else (list ':empty i))))))))))))
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(define pregexp-read-escaped-number
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(lambda (s i n)
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; s[i] = \
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(and (< (+ i 1) n) ;must have at least something following \
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(let ((c (string-ref s (+ i 1))))
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(and (char-numeric? c)
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(let loop ((i (+ i 2)) (r (list c)))
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(if (>= i n)
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(list (string->number
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(list->string (reverse! r))) i)
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(let ((c (string-ref s i)))
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(if (char-numeric? c)
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(loop (+ i 1) (cons c r))
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(list (string->number
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(list->string (reverse! r)))
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i))))))))))
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(define pregexp-read-escaped-char
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(lambda (s i n)
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; s[i] = \
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(and (< (+ i 1) n)
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(let ((c (string-ref s (+ i 1))))
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(case c
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((#\b) (list ':wbdry (+ i 2)))
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((#\B) (list ':not-wbdry (+ i 2)))
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((#\d) (list ':digit (+ i 2)))
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((#\D) (list '(:neg-char :digit) (+ i 2)))
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((#\n) (list #\newline (+ i 2)))
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((#\r) (list #\return (+ i 2)))
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((#\s) (list ':space (+ i 2)))
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((#\S) (list '(:neg-char :space) (+ i 2)))
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((#\t) (list #\tab (+ i 2)))
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((#\w) (list ':word (+ i 2)))
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((#\W) (list '(:neg-char :word) (+ i 2)))
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(else (list c (+ i 2))))))))
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(define pregexp-read-posix-char-class
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(lambda (s i n)
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; lbrack, colon already read
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(let ((neg? #f))
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(let loop ((i i) (r (list #\:)))
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(if (>= i n)
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(error 'pregexp-read-posix-char-class)
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(let ((c (string-ref s i)))
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(cond ((char=? c #\^)
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(set! neg? #t)
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(loop (+ i 1) r))
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((char-alphabetic? c)
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(loop (+ i 1) (cons c r)))
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((char=? c #\:)
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(if (or (>= (+ i 1) n)
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(not (char=? (string-ref s (+ i 1)) #\])))
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(error 'pregexp-read-posix-char-class)
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(let ((posix-class
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(string->symbol
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(list->string (reverse! r)))))
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(list (if neg? (list ':neg-char posix-class)
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posix-class)
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(+ i 2)))))
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(else
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(error 'pregexp-read-posix-char-class)))))))))
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(define pregexp-read-cluster-type
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(lambda (s i n)
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; s[i-1] = left-paren
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(let ((c (string-ref s i)))
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(case c
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((#\?)
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(let ((i (+ i 1)))
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(case (string-ref s i)
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((#\:) (list '() (+ i 1)))
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((#\=) (list '(:lookahead) (+ i 1)))
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((#\!) (list '(:neg-lookahead) (+ i 1)))
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((#\>) (list '(:no-backtrack) (+ i 1)))
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((#\<)
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(list (case (string-ref s (+ i 1))
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((#\=) '(:lookbehind))
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((#\!) '(:neg-lookbehind))
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(else (error 'pregexp-read-cluster-type)))
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(+ i 2)))
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(else (let loop ((i i) (r '()) (inv? #f))
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(let ((c (string-ref s i)))
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(case c
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((#\-) (loop (+ i 1) r #t))
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((#\i) (loop (+ i 1)
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(cons (if inv? ':case-sensitive
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':case-insensitive) r) #f))
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((#\x)
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(set! *pregexp-space-sensitive?* inv?)
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(loop (+ i 1) r #f))
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((#\:) (list r (+ i 1)))
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(else (error 'pregexp-read-cluster-type)))))))))
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(else (list '(:sub) i))))))
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(define pregexp-read-subpattern
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(lambda (s i n)
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(let* ((remember-space-sensitive? *pregexp-space-sensitive?*)
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(ctyp-i (pregexp-read-cluster-type s i n))
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(ctyp (car ctyp-i))
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(i (cadr ctyp-i))
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(vv (pregexp-read-pattern s i n)))
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(set! *pregexp-space-sensitive?* remember-space-sensitive?)
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(let ((vv-re (car vv))
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(vv-i (cadr vv)))
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(if (and (< vv-i n)
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(char=? (string-ref s vv-i) ;(
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#\)))
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(list
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(let loop ((ctyp ctyp) (re vv-re))
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(if (null? ctyp) re
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(loop (cdr ctyp)
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(list (car ctyp) re))))
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(+ vv-i 1))
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(error 'pregexp-read-subpattern))))))
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(define pregexp-wrap-quantifier-if-any
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(lambda (vv s n)
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(let ((re (car vv)))
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(let loop ((i (cadr vv)))
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(if (>= i n) vv
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(let ((c (string-ref s i)))
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(if (and (char-whitespace? c) (not *pregexp-space-sensitive?*))
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(loop (+ i 1))
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(case c
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((#\* #\+ #\? #\{)
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(let* ((new-re (list ':between 'minimal?
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'at-least 'at-most re))
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(new-vv (list new-re 'next-i)))
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(case c
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((#\*) (set-car! (cddr new-re) 0)
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(set-car! (cdddr new-re) #f))
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((#\+) (set-car! (cddr new-re) 1)
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(set-car! (cdddr new-re) #f))
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((#\?) (set-car! (cddr new-re) 0)
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(set-car! (cdddr new-re) 1))
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((#\{) (let ((pq (pregexp-read-nums s (+ i 1) n)))
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(if (not pq)
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(error
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'pregexp-wrap-quantifier-if-any
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"left bracket must be followed by number"))
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(set-car! (cddr new-re) (car pq))
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(set-car! (cdddr new-re) (cadr pq))
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(set! i (caddr pq)))))
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(let loop ((i (+ i 1)))
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(if (>= i n)
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(begin (set-car! (cdr new-re) #f)
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(set-car! (cdr new-vv) i))
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(let ((c (string-ref s i)))
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(cond ((and (char-whitespace? c)
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(not *pregexp-space-sensitive?*))
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(loop (+ i 1)))
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((char=? c #\?)
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(set-car! (cdr new-re) #t)
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(set-car! (cdr new-vv) (+ i 1)))
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(else (set-car! (cdr new-re) #f)
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(set-car! (cdr new-vv) i))))))
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new-vv))
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(else vv)))))))))
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;
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(define pregexp-read-nums
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(lambda (s i n)
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; s[i-1] = {
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; returns (p q k) where s[k] = }
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(let loop ((p '()) (q '()) (k i) (reading 1))
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(if (>= k n) (error 'pregexp-read-nums))
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(let ((c (string-ref s k)))
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(cond ((char-numeric? c)
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(if (= reading 1)
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(loop (cons c p) q (+ k 1) 1)
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(loop p (cons c q) (+ k 1) 2)))
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((and (char-whitespace? c) (not *pregexp-space-sensitive?*))
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(loop p q (+ k 1) reading))
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((and (char=? c #\,) (= reading 1))
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(loop p q (+ k 1) 2))
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((char=? c #\})
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(let ((p (string->number (list->string (reverse! p))))
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(q (string->number (list->string (reverse! q)))))
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(cond ((and (not p) (= reading 1)) (list 0 #f k))
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((= reading 1) (list p p k))
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(else (list p q k)))))
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(else #f))))))
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(define pregexp-invert-char-list
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(lambda (vv)
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(set-car! (car vv) ':none-of-chars)
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vv))
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;
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(define pregexp-read-char-list
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(lambda (s i n)
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(let loop ((r '()) (i i))
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(if (>= i n)
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(error 'pregexp-read-char-list
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"character class ended too soon")
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(let ((c (string-ref s i)))
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(case c
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((#\]) (if (null? r)
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(loop (cons c r) (+ i 1))
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(list (cons ':one-of-chars (reverse! r))
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(+ i 1))))
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((#\\)
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(let ((char-i (pregexp-read-escaped-char s i n)))
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(if char-i (loop (cons (car char-i) r) (cadr char-i))
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(error 'pregexp-read-char-list "backslash"))))
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((#\-) (let ((c-prev (car r)))
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(if (char? c-prev)
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(loop (cons (list ':char-range c-prev
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(string-ref s (+ i 1))) (cdr r))
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(+ i 2))
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(loop (cons c r) (+ i 1)))))
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((#\[) (if (char=? (string-ref s (+ i 1)) #\:)
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(let ((posix-char-class-i
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(pregexp-read-posix-char-class s (+ i 2) n)))
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(loop (cons (car posix-char-class-i) r)
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(cadr posix-char-class-i)))
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(loop (cons c r) (+ i 1))))
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(else (loop (cons c r) (+ i 1)))))))))
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;
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(define pregexp-string-match
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(lambda (s1 s i n sk fk)
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(let ((n1 (string-length s1)))
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(if (> n1 n) (fk)
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(let loop ((j 0) (k i))
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(cond ((>= j n1) (sk k))
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((>= k n) (fk))
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((char=? (string-ref s1 j) (string-ref s k))
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(loop (+ j 1) (+ k 1)))
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(else (fk))))))))
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(define pregexp-char-word?
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(lambda (c)
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;too restrictive for Scheme but this
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;is what \w is in most regexp notations
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(or (char-alphabetic? c)
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(char-numeric? c)
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(char=? c #\_))))
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(define pregexp-at-word-boundary?
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(lambda (s i n)
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(or (= i 0) (>= i n)
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(let ((c/i (string-ref s i))
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(c/i-1 (string-ref s (- i 1))))
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(let ((c/i/w? (pregexp-check-if-in-char-class?
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c/i ':word))
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(c/i-1/w? (pregexp-check-if-in-char-class?
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c/i-1 ':word)))
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(or (and c/i/w? (not c/i-1/w?))
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(and (not c/i/w?) c/i-1/w?)))))))
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(define pregexp-check-if-in-char-class?
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(lambda (c char-class)
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(case char-class
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((:any) (not (char=? c #\newline)))
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;
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((:alnum) (or (char-alphabetic? c) (char-numeric? c)))
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((:alpha) (char-alphabetic? c))
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((:ascii) (< (char->integer c) 128))
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((:blank) (or (char=? c #\space) (char=? c #\tab)))
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((:cntrl) (< (char->integer c) 32))
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((:digit) (char-numeric? c))
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((:graph) (and (>= (char->integer c) 32)
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(not (char-whitespace? c))))
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((:lower) (char-lower-case? c))
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((:print) (>= (char->integer c) 32))
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((:punct) (and (>= (char->integer c) 32)
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(not (char-whitespace? c))
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(not (char-alphabetic? c))
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(not (char-numeric? c))))
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((:space) (char-whitespace? c))
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((:upper) (char-upper-case? c))
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((:word) (or (char-alphabetic? c)
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(char-numeric? c)
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(char=? c #\_)))
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((:xdigit) (or (char-numeric? c)
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(char-ci=? c #\a) (char-ci=? c #\b)
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(char-ci=? c #\c) (char-ci=? c #\d)
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(char-ci=? c #\e) (char-ci=? c #\f)))
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(else (error 'pregexp-check-if-in-char-class?)))))
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(define pregexp-list-ref
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(lambda (s i)
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;like list-ref but returns #f if index is
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;out of bounds
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(let loop ((s s) (k 0))
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(cond ((null? s) #f)
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((= k i) (car s))
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(else (loop (cdr s) (+ k 1)))))))
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;re is a compiled regexp. It's a list that can't be
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;nil. pregexp-match-positions-aux returns a 2-elt list whose
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;car is the string-index following the matched
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;portion and whose cadr contains the submatches.
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;The proc returns false if there's no match.
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;Am spelling loop- as loup- because these shouldn't
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;be translated into CL loops by scm2cl (although
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;they are tail-recursive in Scheme)
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(define pregexp-match-positions-aux
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(lambda (re s start n i)
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(let ((case-sensitive? #t))
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(let sub ((re re) (i i) (backrefs '()) (sk list) (fk (lambda () #f)))
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;(printf "sub ~s ~s~%" i re)
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(cond ((eqv? re ':bos)
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(if (= i start) (sk i backrefs) (fk)))
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((eqv? re ':eos)
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(if (>= i n) (sk i backrefs) (fk)))
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((eqv? re ':empty)
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(sk i backrefs))
|
||||
((eqv? re ':wbdry)
|
||||
(if (pregexp-at-word-boundary? s i n)
|
||||
(sk i backrefs)
|
||||
(fk)))
|
||||
((eqv? re ':not-wbdry)
|
||||
(if (pregexp-at-word-boundary? s i n)
|
||||
(fk)
|
||||
(sk i backrefs)))
|
||||
((and (char? re) (< i n))
|
||||
(if ((if case-sensitive? char=? char-ci=?)
|
||||
(string-ref s i) re)
|
||||
(sk (+ i 1) backrefs) (fk)))
|
||||
((and (not (pair? re)) (< i n))
|
||||
(if (pregexp-check-if-in-char-class?
|
||||
(string-ref s i) re)
|
||||
(sk (+ i 1) backrefs) (fk)))
|
||||
((and (pair? re) (eqv? (car re) ':char-range) (< i n))
|
||||
(let ((c (string-ref s i)))
|
||||
(if (let ((c< (if case-sensitive? char<=? char-ci<=?)))
|
||||
(and (c< (cadr re) c)
|
||||
(c< c (caddr re))))
|
||||
(sk (+ i 1) backrefs) (fk))))
|
||||
((pair? re)
|
||||
(case (car re)
|
||||
((:char-range)
|
||||
(if (>= i n) (fk) (error 'pregexp-match-positions-aux)))
|
||||
((:one-of-chars)
|
||||
(if (>= i n) (fk)
|
||||
(let loup-one-of-chars ((chars (cdr re)))
|
||||
(if (null? chars) (fk)
|
||||
(sub (car chars) i backrefs sk
|
||||
(lambda ()
|
||||
(loup-one-of-chars (cdr chars))))))))
|
||||
((:neg-char)
|
||||
(if (>= i n) (fk)
|
||||
(sub (cadr re) i backrefs
|
||||
(lambda (i1 backrefs1) (fk))
|
||||
(lambda () (sk (+ i 1) backrefs)))))
|
||||
((:seq)
|
||||
(let loup-seq ((res (cdr re)) (i i) (backrefs backrefs))
|
||||
(if (null? res) (sk i backrefs)
|
||||
(sub (car res) i backrefs
|
||||
(lambda (i1 backrefs1)
|
||||
(loup-seq (cdr res) i1 backrefs1))
|
||||
fk))))
|
||||
((:or)
|
||||
(let loup-or ((res (cdr re)))
|
||||
(if (null? res) (fk)
|
||||
(sub (car res) i backrefs
|
||||
(lambda (i1 backrefs1)
|
||||
(or (sk i1 backrefs1)
|
||||
(loup-or (cdr res))))
|
||||
(lambda () (loup-or (cdr res)))))))
|
||||
((:backref)
|
||||
(let ((backref (pregexp-list-ref backrefs (cadr re))))
|
||||
(if backref
|
||||
(pregexp-string-match
|
||||
(substring s (car backref) (cdr backref))
|
||||
s i n (lambda (i) (sk i backrefs)) fk)
|
||||
(sk i backrefs))))
|
||||
((:sub)
|
||||
(let* ((sub-backref (cons i i))
|
||||
(backrefs (append backrefs (list sub-backref))))
|
||||
(sub (cadr re) i backrefs
|
||||
(lambda (i1 backrefs1)
|
||||
(set-cdr! sub-backref i1)
|
||||
(sk i1 backrefs1)) fk)))
|
||||
((:lookahead)
|
||||
(let ((found-it?
|
||||
(sub (cadr re) i backrefs
|
||||
list (lambda () #f))))
|
||||
(if found-it? (sk i backrefs) (fk))))
|
||||
((:neg-lookahead)
|
||||
(let ((found-it?
|
||||
(sub (cadr re) i backrefs
|
||||
list (lambda () #f))))
|
||||
(if found-it? (fk) (sk i backrefs))))
|
||||
((:lookbehind)
|
||||
(let ((n-actual n)) (set! n i)
|
||||
(let ((found-it?
|
||||
(sub (list ':seq '(:between #f 0 #f :any)
|
||||
(cadr re) ':eos) 0 backrefs
|
||||
list (lambda () #f))))
|
||||
(set! n n-actual)
|
||||
(if found-it? (sk i backrefs) (fk)))))
|
||||
((:neg-lookbehind)
|
||||
(let ((n-actual n)) (set! n i)
|
||||
(let ((found-it?
|
||||
(sub (list ':seq '(:between #f 0 #f :any)
|
||||
(cadr re) ':eos) 0 backrefs
|
||||
list (lambda () #f))))
|
||||
(set! n n-actual)
|
||||
(if found-it? (fk) (sk i backrefs)))))
|
||||
((:no-backtrack)
|
||||
(let ((found-it? (sub (cadr re) i backrefs
|
||||
list (lambda () #f))))
|
||||
(if found-it?
|
||||
(sk (car found-it?) (cadr found-it?))
|
||||
(fk))))
|
||||
((:case-sensitive :case-insensitive)
|
||||
(let ((old case-sensitive?))
|
||||
(set! case-sensitive?
|
||||
(eqv? (car re) ':case-sensitive))
|
||||
(sub (cadr re) i backrefs
|
||||
(lambda (i1 backrefs1)
|
||||
(set! case-sensitive? old)
|
||||
(sk i1 backrefs1))
|
||||
(lambda ()
|
||||
(set! case-sensitive? old)
|
||||
(fk)))))
|
||||
((:between)
|
||||
(let* ((maximal? (not (cadr re)))
|
||||
(p (caddr re)) (q (cadddr re))
|
||||
(re (car (cddddr re)))
|
||||
(subpat? (and (pair? re) (eqv? (car re) ':sub))))
|
||||
(let loup-p ((k 0) (i i) (cbackrefs 'no-match-yet))
|
||||
(if (< k p)
|
||||
(sub re i backrefs
|
||||
(lambda (i1 backrefs1)
|
||||
(loup-p (+ k 1) i1 backrefs1))
|
||||
fk)
|
||||
(let ((q (and q (- q p))))
|
||||
(let loup-q ((k 0) (i i) (cbackrefs cbackrefs))
|
||||
(let ((fk (lambda ()
|
||||
(sk i (if (eqv? cbackrefs
|
||||
'no-match-yet)
|
||||
(if subpat?
|
||||
(append backrefs
|
||||
(list #f))
|
||||
backrefs)
|
||||
cbackrefs)))))
|
||||
(if (and q (>= k q)) (fk)
|
||||
(if maximal?
|
||||
(sub re i backrefs
|
||||
(lambda (i1 backrefs1)
|
||||
(or (loup-q (+ k 1) i1 backrefs1)
|
||||
(fk)))
|
||||
fk)
|
||||
(or (fk)
|
||||
(sub re i backrefs
|
||||
(lambda (i1 backrefs1)
|
||||
(loup-q (+ k 1) i1 backrefs1))
|
||||
fk)))))))))))
|
||||
(else (error 'pregexp-match-positions-aux))))
|
||||
((>= i n) (fk))
|
||||
(else (error 'pregexp-match-positions-aux)))))))
|
||||
|
||||
(define pregexp-replace-aux
|
||||
(lambda (str ins n backrefs)
|
||||
(let loop ((i 0) (r ""))
|
||||
(if (>= i n) r
|
||||
(let ((c (string-ref ins i)))
|
||||
(if (char=? c #\\)
|
||||
(let* ((br-i (pregexp-read-escaped-number ins i n))
|
||||
(br (if br-i (car br-i)
|
||||
(if (char=? (string-ref ins (+ i 1)) #\&) 0
|
||||
#f)))
|
||||
(i (if br-i (cadr br-i)
|
||||
(if br (+ i 2)
|
||||
(+ i 1)))))
|
||||
(if (not br)
|
||||
(let ((c2 (string-ref ins i)))
|
||||
(loop (+ i 1)
|
||||
(if (char=? c2 #\$) r
|
||||
(string-append r (string c2)))))
|
||||
(loop i
|
||||
(let ((backref (pregexp-list-ref backrefs br)))
|
||||
(if backref
|
||||
(string-append r
|
||||
(substring str (car backref) (cdr backref)))
|
||||
r)))))
|
||||
(loop (+ i 1) (string-append r (string c)))))))))
|
||||
|
||||
(define pregexp
|
||||
(lambda (s)
|
||||
(set! *pregexp-space-sensitive?* #t) ;in case it got corrupted
|
||||
(list ':sub (car (pregexp-read-pattern s 0 (string-length s))))))
|
||||
|
||||
(define pregexp-match-positions
|
||||
(lambda (pat str . opt-args)
|
||||
(let* ((pat (if (string? pat) (pregexp pat) pat))
|
||||
(start (if (null? opt-args) 0
|
||||
(let ((start (car opt-args)))
|
||||
(set! opt-args (cdr opt-args))
|
||||
start)))
|
||||
(end (if (null? opt-args) (string-length str)
|
||||
(car opt-args))))
|
||||
(let loop ((i start))
|
||||
(and (<= i end)
|
||||
(let ((vv (pregexp-match-positions-aux pat str start end i)))
|
||||
(if vv
|
||||
(cadr vv)
|
||||
(loop (+ i 1)))))))))
|
||||
|
||||
(define pregexp-match
|
||||
(lambda (pat str . opt-args)
|
||||
(let ((ix-prs (apply pregexp-match-positions pat str opt-args)))
|
||||
(and ix-prs
|
||||
(map
|
||||
(lambda (ix-pr)
|
||||
(and ix-pr
|
||||
(substring str (car ix-pr) (cdr ix-pr))))
|
||||
ix-prs)))))
|
||||
|
||||
(define pregexp-split
|
||||
(lambda (pat str)
|
||||
;split str into substrings, using pat as delimiter
|
||||
(let ((n (string-length str)))
|
||||
(let loop ((i 0) (r '()) (picked-up-one-undelimited-char? #f))
|
||||
(cond ((>= i n) (reverse! r))
|
||||
((pregexp-match-positions pat str i n)
|
||||
=>
|
||||
(lambda (y)
|
||||
(let ((jk (car y)))
|
||||
(let ((j (car jk)) (k (cdr jk)))
|
||||
;(printf "j = ~a; k = ~a; i = ~a~n" j k i)
|
||||
(cond ((= j k)
|
||||
;(printf "producing ~s~n" (substring str i (+ j 1)))
|
||||
(loop (+ k 1)
|
||||
(cons (substring str i (+ j 1)) r) #t))
|
||||
((and (= j i) picked-up-one-undelimited-char?)
|
||||
(loop k r #f))
|
||||
(else
|
||||
;(printf "producing ~s~n" (substring str i j))
|
||||
(loop k (cons (substring str i j) r) #f)))))))
|
||||
(else (loop n (cons (substring str i n) r) #f)))))))
|
||||
|
||||
(define pregexp-replace
|
||||
(lambda (pat str ins)
|
||||
(let* ((n (string-length str))
|
||||
(pp (pregexp-match-positions pat str 0 n)))
|
||||
(if (not pp) str
|
||||
(let ((ins-len (string-length ins))
|
||||
(m-i (caar pp))
|
||||
(m-n (cdar pp)))
|
||||
(string-append
|
||||
(substring str 0 m-i)
|
||||
(pregexp-replace-aux str ins ins-len pp)
|
||||
(substring str m-n n)))))))
|
||||
|
||||
(define pregexp-replace*
|
||||
(lambda (pat str ins)
|
||||
(let ((pat (if (string? pat) (pregexp pat) pat))
|
||||
(n (string-length str))
|
||||
(ins-len (string-length ins)))
|
||||
(let loop ((i 0) (r ""))
|
||||
(let ((pp (pregexp-match-positions pat str i n)))
|
||||
(if pp
|
||||
(loop (cdar pp)
|
||||
(string-append r
|
||||
(substring str i (caar pp))
|
||||
(pregexp-replace-aux str ins ins-len pp)))
|
||||
(string-append r
|
||||
(substring str i n))))))))
|
||||
|
||||
;eof
|
||||
)
|
||||
Loading…
Reference in New Issue
Block a user