*** empty log message ***

original commit: 631f97d1b63162787ab940fddbef588e44b184b2

collects/parser-tools/lex.ss

@@ -144,32 +144,66 @@
   (define-struct lex-buffer (ip from to offset line col line-lengths))
 
   ;; make-lex-buf: input-port -> lex-buf
-  (define (make-lex-buf ip)
+  (define make-lex-buf
-    (make-lex-buffer ip null null 1 1 1 null))
+    (case-lambda 
+     ((ip) 
+      (cond
+       ((not (input-port? ip))
+	(raise-type-error 'make-lex-buf "input-port" 0 ip))
+       (else
+	(make-lex-buffer ip null null 0 0 0 null))))
+     ((ip offsets)
+      (cond
+       ((not (input-port? ip))
+	(raise-type-error 'make-lex-buf "input-port" 0 ip offsets))
+       ((or (not (= 3 (length offsets)))
+	    (not (andmap integer? offsets))
+	    (not (andmap exact? offsets))
+	    (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 (caddr offsets) (car offsets) (cadr offsets) null))))))
 
   ;; next-char: lex-buf -> c
   ;; gets the next character from the buffer
   (define (next-char lb)
-    (let ((char-in
+    (let ((get-next
-	   (cond
+	   (lambda ()
-	    ((null? (lex-buffer-from lb)) 
+	     (cond
-	     (read-char (lex-buffer-ip lb)))
+	      ((null? (lex-buffer-from lb)) 
-	    (else (begin0
+	       (read-char (lex-buffer-ip lb)))
-		   (car (lex-buffer-from lb))
+	      (else 
-		   (set-lex-buffer-from! lb (cdr (lex-buffer-from lb))))))))
+	       (begin0
-      (set-lex-buffer-to! lb (cons char-in (lex-buffer-to lb)))
+		(car (lex-buffer-from lb))
-      (cond 
+		(set-lex-buffer-from! lb (cdr (lex-buffer-from lb)))))))))
-       ((eq? #\newline char-in)
+      (let ((char-in
-	(set-lex-buffer-line-lengths!
+	     (let ((real-char (get-next)))
-	 lb
+	       (if (char=? #\return real-char)
-	 (cons (lex-buffer-col lb)
+		   (let ((second-char (get-next)))
-	       (lex-buffer-line-lengths lb)))
+		     (if (not (char=? second-char #\newline))
-	(set-lex-buffer-line! lb (add1 (lex-buffer-line lb)))
+			 (set-lex-buffer-from! 
-	(set-lex-buffer-col! lb 1))
+			  lb 
-       (else
+			  (cons second-char (lex-buffer-from lb))))
-	(set-lex-buffer-col! lb (add1 (lex-buffer-col lb)))))
+		     #\newline)
-      (set-lex-buffer-offset! lb (add1 (lex-buffer-offset lb)))
+		   real-char))))
-      char-in))
+	(set-lex-buffer-to! lb (cons char-in (lex-buffer-to lb)))
+	(cond 
+	 ((char=? #\tab char-in)
+	  (let ((skip-amt (- 8 (modulo (lex-buffer-col lb) 8))))
+	    (set-lex-buffer-col! lb (+ skip-amt (lex-buffer-col lb)))
+	    (set-lex-buffer-offset! lb (+ skip-amt (lex-buffer-col lb)))))
+	 ((char=? #\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 0)
+	  (set-lex-buffer-offset! lb (add1 (lex-buffer-offset lb))))
+	 (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
@@ -189,7 +223,7 @@
 		 ((= 0 num-to-add) (values from to))
 		 (else
 		  (cond
-		   ((eq? #\newline (car from))
+		   ((char=? #\newline (car from))
 		    (set-lex-buffer-line! 
 		     lb
 		     (sub1 (lex-buffer-line lb)))