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@ -85,47 +85,47 @@
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(not (andmap (lambda (x) (>= x 0)) offsets)))
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(raise-type-error 'make-lex-buf "list of 3 non-negative exact integers" 1 ip offsets))
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(else
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(make-lex-buffer ip null null (add1 (caddr offsets)) (add1 (car offsets)) (add1 (cadr offsets)) null null))))))
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(make-lex-buffer ip null null (caddr offsets) (car offsets) (cadr offsets) null null))))))
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(define (get-next lb)
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(cond
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((null? (lex-buffer-from lb))
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(read-char (lex-buffer-ip lb)))
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(else
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(begin0
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(car (lex-buffer-from lb))
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(set-lex-buffer-from! lb (cdr (lex-buffer-from lb)))))))
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;; next-char: lex-buf -> c
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;; gets the next character from the buffer
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(define (next-char lb)
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(let ((get-next
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(lambda ()
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(cond
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((null? (lex-buffer-from lb))
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(read-char (lex-buffer-ip lb)))
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(else
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(begin0
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(car (lex-buffer-from lb))
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(set-lex-buffer-from! lb (cdr (lex-buffer-from lb)))))))))
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(let ((char-in
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(let ((real-char (get-next)))
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(if (eq? #\return real-char)
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(let ((second-char (get-next)))
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(if (not (eq? second-char #\newline))
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(set-lex-buffer-from!
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lb
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(cons second-char (lex-buffer-from lb))))
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#\newline)
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real-char))))
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(set-lex-buffer-to! lb (cons char-in (lex-buffer-to lb)))
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(cond
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((eq? #\tab char-in)
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(let ((skip-amt (- 8 (modulo (lex-buffer-col lb) 8))))
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(set-lex-buffer-tab-skips! lb (cons skip-amt (lex-buffer-tab-skips lb)))
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(set-lex-buffer-col! lb (+ skip-amt (lex-buffer-col lb)))))
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((eq? #\newline char-in)
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(set-lex-buffer-line-lengths!
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lb
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(cons (lex-buffer-col lb)
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(lex-buffer-line-lengths lb)))
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(set-lex-buffer-line! lb (add1 (lex-buffer-line lb)))
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(set-lex-buffer-col! lb 1))
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(else
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(set-lex-buffer-col! lb (add1 (lex-buffer-col lb)))))
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(set-lex-buffer-offset! lb (add1 (lex-buffer-offset lb)))
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char-in)))
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(let ((char-in
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(let ((real-char (get-next lb)))
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(if (eq? #\return real-char)
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(let ((second-char (get-next)))
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(if (not (eq? second-char #\newline))
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(set-lex-buffer-from!
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lb
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(cons second-char (lex-buffer-from lb))))
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#\newline)
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real-char))))
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(set-lex-buffer-to! lb (cons char-in (lex-buffer-to lb)))
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(cond
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((eq? #\tab char-in)
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(let ((skip-amt (- 8 (modulo (lex-buffer-col lb) 8))))
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(set-lex-buffer-tab-skips! lb (cons skip-amt (lex-buffer-tab-skips lb)))
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(set-lex-buffer-col! lb (+ skip-amt (lex-buffer-col lb)))))
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((eq? #\newline char-in)
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(set-lex-buffer-line-lengths!
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lb
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(cons (lex-buffer-col lb)
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(lex-buffer-line-lengths lb)))
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(set-lex-buffer-line! lb (add1 (lex-buffer-line lb)))
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(set-lex-buffer-col! lb 1))
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(else
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(set-lex-buffer-col! lb (add1 (lex-buffer-col lb)))))
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(set-lex-buffer-offset! lb (add1 (lex-buffer-offset lb)))
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char-in))
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;; push-back: lex-buf * int -> c list
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;; pushes the last read i characters back to be read again
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