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  1. ; trailing comments
  2.  
  3. (define (tc? str)     ; true when a trailing comment is found, else false
  4.   (let loop ((xs (string->list str)) (inquotes #f))     ; initialize loop
  5.     (cond ((null? xs) #f)           ; reached end-of-line without comment
  6.           ((and inquotes (char=? (car xs) #\"))            ; end of quote
  7.             (loop (cdr xs) #f))       ; initialize for next quoted string
  8.           ((and inquotes (char=? (car xs) #\\) (pair? (cdr xs))) ; escape
  9.             (loop (cddr xs) #t))   ; skip backslash and escaped character
  10.           (inquotes (loop (cdr xs) #t))                  ; continue quote
  11.           ((char=? (car xs) #\") (loop (cdr xs) #t))        ; start quote
  12.           ((char=? (car xs) #\#) #t)             ; found trailing comment
  13.           (else (loop (cdr xs) #f)))))                   ; next character
  14.  
  15. (display (tc? "x = \"# This is fine\""))   (newline)
  16. (display (tc? "\"This \\# is fine too\"")) (newline)
  17. (display (tc? "x = \"\" # This is not\"")) (newline)
Success #stdin #stdout 0s 7992KB
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#f
#f
#t
https://ideone.com/AzDwgg
language:
Scheme (chicken 4.13)
created:
3 years ago
visibility:
secret

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