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original commit: 6986dd5d52829308189ef6e3d6f5be94a28186cc
tokens
Scott Owens 23 years ago
parent 67313d8a93
commit db43a04859

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

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