suzanne.soy/scribble-enhanced
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Changing decode-string so it avoids allocation and interns the individual string components.

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original commit: 2f4671235c322f3450b0633cd866f18b95f58f13
This commit is contained in:
Danny Yoo 2012-06-25 16:55:01 -04:00 committed by Matthew Flatt
parent 1efd01584e
commit db64a47dd7
1 changed files with 21 additions and 13 deletions
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34
collects/scribble/decode.rkt
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@ -92,20 +92,28 @@
[s (regexp-replace* #rx" $" s "")])
(datum-intern-literal s)))
(define (decode-string s)
(let loop ([l '((#rx"---" mdash)
(#rx"--" ndash)
(#rx"``" ldquo)
(#rx"''" rdquo)
(#rx"'" rsquo))])
(cond [(null? l) (list s)]
[(regexp-match-positions (caar l) s)
=> (lambda (m)
(datum-intern-literal
(append (decode-string (substring s 0 (caar m)))
(cdar l)
(decode-string (substring s (cdar m))))))]
[else (loop (cdr l))])))
(define pattern #rx"(---|--|``|''|')")
(let loop ([start 0])
(cond
[(regexp-match-positions pattern s start)
=> (lambda (m)
(define the-match (substring s (caar m) (cdar m)))
(list* (datum-intern-literal (substring s start (caar m)))
(cond
[(string=? the-match "---") 'mdash]
[(string=? the-match "--") 'ndash]
[(string=? the-match "``") 'ldquo]
[(string=? the-match "''") 'rdquo]
[(string=? the-match "'") 'rsquo])
(loop (cdar m))))]
;; Common case: nothing to decode, so don't copy strings.
[(= start 0)
(list (datum-intern-literal s))]
[else
(list (datum-intern-literal (substring s start)))])))
(define (line-break? v)
(equal? v "\n"))